Possessive pronoun vs definite article in this sentence

Question

In some languages, such as French and Spanish, it's ungrammatical or at least uncommon to use possessive pronouns to refer to parts of the body in some contexts: People say "the head," "the face" to refer to their own face, at least in some circumstances or kinds of constructions. But when the noun as an object is not a body part, possessive pronouns are ungrammatical or strange, at least in many cases.

It seems that English might have different grammar in this respect. I don't know what rules dictate the use of a definite article OR a possessive pronoun in my sentence but my intuition is B is more correct. I don't know why. Can anyone tell me whether A is also acceptable and if not, why only B is right?

A. In his dissertation on biodiversity submitted yesterday, John explored ... (extraneous information omitted)
B. In the dissertation on biodiversity submitted yesterday, ...

Answer 1

English is probably different from your native/other language(s) in this way:

It's common to use the word "possession" in grammar to mean a more general kind of relationship indicated by a "possessive pronoun".

For example, I don't own "my sister". (I did previously, but I sold her because she is somewhat impolite.)

Both of the sentences in your example are grammatical and natural.

We use the definite article, the, to introduce nouns (noun phrases) when we know or believe that the hearer shares information with us. In other words, if I ask, "Did you like the movie?" I assume or know that you will understand which movie I am talking about.

In your example, we would usually only use the definite article if we had just previously mentioned that dissertation, and/or if it was not important in our mind whose it was when we speak:

John worked very hard on his dissertation and submitted it yesterday. He told me that he was fairly proud of the dissertation and had high hopes that it would be accepted.

For body parts, it's more common in English to use possessive pronouns, and would sometimes sound a bit odd or be ungrammatical to use an article if we know whose body part we are referring to.

I hurt the hand

Ungrammatical if I mean that I hurt my hand.

The dog licked her face.

The dog licked her in the face.

Both of these are grammatical and natural.

I cannot give a very complete answer, at least right now. But I suggest that you might search for information specifically about possessive pronouns and body parts, since this is a common issue for English learners from some (or perhaps most) backgrounds.