The correct answer is:
B. Predicate.
The predicate is necessary to complete the sentence.

A parallel structure is a sentence that repeats similar word structures twice.
In this case, the correct answer is sentence 3.
For example: She not only wanted a dog, but also wanted a cat.
Answer:
D. she wants to see if the carnival comes again.
Just answered it on USA Test Prep and got it right. (:
Answer: D
Explanation: "less" almost always qualifies as an adjective, because it's describing a noun, that being support, which is a thing/idea.
You would use it as an adverb if you were using it to describe or add more information to a verb. Ex. "I've been trying to work <em>less</em> on the weekends." Work is a verb, so less would qualify as an adverb here.