In the proverb, "a stitch in time saves nine," the words nine and time illustrate

a. imperfect rhyme
b. eye rhyme
c. consonance

The answer is "option C. consonance".

Consonance alludes to the sounds which are repetitive delivered by consonants inside a sentence or expression. This repetition frequently happens with hardly a pause in between, for example if we look at the given proverb "A stitch in time saves nine," the words time and nine are giving the repetitive sounds.