Select the most appropriate option that can substitute the highlighted word in the given idiom.
She is an awful bore; she is always blowing her own saxophone.

Correct option is C

The correct idiom to use is "blowing her own trumpet," which means to boast about oneself.
Blowing someone's own trumpet:To boast or brag about one’s own achievements.

Sentence use:
She never misses a chance to blow her own trumpet about her academic scores.

Similar idioms:

Pat oneself on the back – To praise oneself.
Toot your own horn – Same as blow your own trumpet; to brag.
Full of oneself – Having too high an opinion of oneself.