B) Why do you think the composer chose to use a 3/8 time signature for Hedwig’s Theme?

Ease of note reading.

Explanation:

The time signature of a piece tells us about its rhythm. Hedwig's Theme is in 3/8 time. The upper number indicates the number of beats in each measure, and the lower number indicates the note value that is worth one beat.

your word would be isle.

isle is an island or peninsula especially a small one.

if you add the letter "a" you get aisle, which is a passage between 2 rows of something like chairs, shelves, or something else.