Answer:
C. Beside her bed.
Explanation:
An adjectival phrase, as its names refer, is a group of words that describe a noun or pronoun and act as an adjective.
There is a little trick to identify the adjectival phrases and it is that, usually, the first word with which the phrases begin is whether an adverb or a preposition.
In the question given the option C starts with a preposition (Beside) and the phrase is describing the place where the dress is hanging.
I hope this answer helps you.
