Either had been or was

Question

In the following question sentence

When he arrived to attend the wedding of his brother, he ______ in dark suit.

I have only two options to fill

1. Had dressed

2. Was dressed

Which one should I use, I am not able to find difference between their usage.

Answer 1

Use the second. The first is acceptable, perhaps, but it sounds odd because you are specifying the time with "when"... it causes the listener to wonder why you've worded it strangely.

Also, you need an article before dark suit.

I've changed the wording a bit to make it slightly more natural:

When he arrived at his brother's wedding, he was dressed in a dark suit.

Answer 2

When we describe a point of time. So we should use “was dressed”.

But when we are describing about a period of time in the past, we use “had been”. For example “In the night he arrived to attend the wedding of his brother, he had been in dark suit”

In your question it was just a point of time (when he arrived = at the time he arrived). So we should use “was dressed”