Logical prediction and parallelism

Question

I am preparing for the GMAT exam, and this was a practice question.

Please explain why E is the correct answer choice to the following question:

Choose a grammatically correct option of the bold part:

A ruined structure found at Aqaba, Jordan, was probably a church, as indicated in its eastward orientation and by its overall plan, as well as artifacts, such as glass oil-lamp fragments, found at the site.

A. A ruined structure found at Aqaba, Jordan, was probably a church, as indicated in its eastward orientation and by its overall plan, as well as

B. A ruined structure found at Aqaba, Jordan, once probably being a church, was indicated by its eastward orientation, overall plan, and

C. Indicating that a ruined structure found at Aqaba, Jordan, was probably a church were its eastward orientation and overall plan, but also the

D. A ruined structure found at Aqaba, Jordan, was probably a church, as indicates its eastward orientation and overall plan, as well as the

E. That a ruined structure found at Aqaba, Jordan, was probably a church is indicated by its eastward orientation and overall plan, as well as by the

The given sentence may or may not have errors in the bold part. Question is to choose a grammatically correct answer from options.

My reasons:

Option A: Has parallelism error- by its overall plan, as well as should be by its overall plan, as well as by

Option B: Changes the intended meaning. It says Structure was indicated in its ...

Option C: Indicating .... were are wrongly framed

Option D: Cant find any error

Option E: Use of that is wrong.

Also, Can you please tell me if my reasons are correct?

Answer 1

[That a ruined structure found at Aqaba, Jordan, was probably a church] is indicated by its eastward orientation and overall plan, as well as by the [X]

The subject of the verb is is the entire phrase "That a ruined structure ... probably a church".

When you make a whole phrase (with its own subject and verb) the subject of a sentence, the word that is needed in front of it.

Answer 2

I don’t know why I am answering to you honestly speaking but I would try to do so because no native speaker doesn't answer. (So please feel free to downvote or edit or do anything to mine (to native speakers)).

First, since I am not a native speaker, I will quote my own country's language sites' because trying to do so in English will take enormous of time.

Thus said, the conclusion is E is the correct "option".

Starting with that makes the sentence as the Noun Subject, as you can find at this site (in Japanese but I will translate.)

such as

彼が正直者であるというのは嘘だ。(No need to translate(See below))

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That he is an honest is a lie.

The choice E has the same grammar with the above sentence, starting with that and making it the Noun Subject. Thus you can start with "that".

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My reasons:

Option A: Has parallelism error- by its overall plan, as well as should be by its overall plan, as well as by

No it is not. The option A is the exact copy of the sentence in the question. Thus The option A can not be the "option".

Option B: Changes the intended meaning. It says Structure was indicated in its ...

No it is not. The "problem" lies in this line. "once probably being a church," it sounds to me for over a long period of time it remained as the church. This line is changing the original line in the question.

Option C: Indicating .... were are wrongly framed

No, simply saying the option C doesn't make sense at all.

Option D: Cant find any error

There is an error here. "as indicates its eastward orientation and overall plan, as well as the" It is not clarified at all what indicates. If it were "as indicated" it would be fine.

I hope I could've help you even a bit.

Thank you.