Synonym of ACERB

Answer: Option B

Unwilling : not ready, eager, or prepared to do something.
Harsh : unpleasantly rough or jarring to the senses.
Dangerous : able or likely to cause harm or injury.
Foreign : of, from, in, or characteristic of a country or language other than one's own.
Acerb : (especially of a comment or style of speaking) sharp and forthright.

Synonym of Acerb is Harsh