Anoun clause does not function as a modifier.
a. true
b. false?

The answer is, option A. True. A noun clause does not function as a modifier. A noun clause cannot function as a modifier because unlike adjectives and adverbs, this clause cannot be independent by itself and they can only function within a main sentence. 

1. I hope you're not joking

2. I'm sorry if its true

3. go to a therapist