Fill in the blank with the correct Adverb - He was kind _____ to help…

The correct answer is Option (4) → enough

An adverb is a word that tells how, when, where or how much something happens. It can also describe an adjective or another adverb, for example she sings sweetly, very hot.

Complete sentence: He was kind enough to help me. "He was kind enough to help me" means he was so kind that he helped me.

Option	What it tells	Example
(1) always	"Always" is an adverb of frequency that normally comes before the main verb or after "be" ("He was always kind"). "Kind always to help me" is not English.	–
(2) much	"Much" does not follow a plain adjective like "kind". We say "very kind" or "much kinder".	–
(3) since	"Since" refers to time or reason (since Monday, since you ask). "Kind since to help me" makes no sense.	–
(4) enough (answer)	As an adverb, enough means to the necessary degree. It comes after the adjective it modifies and is often followed by a to-infinitive: adjective + enough + to + verb.	She is old enough to travel alone.

Contrast: enough comes after the adjective (kind enough). Very comes before it (very kind).