The unnecessary adjective in the sentence "His nervous fidgeting upset the others," is nervous. Option B is correct.
Adjectives are words that describe or modify other words in a sentence, making your writing and speaking much more specific, and more interesting. Adjectives modify nouns. Adjectives do not modify verbs or adverbs or other adjectives.
In this case, nervous means easily agitated or alarmed, while fidgeting means to be impatient or uneasy.
