In this case it would be 's
A. How many s's are in Mississippi?
The rule is use an apostrophe s to form plural of single letters.
Hope this helps.
B. a formal poem using extensive repetition.
C. a favorite technique of John Donne.
D. a narrative poem written in blank verse.
B. too much blank verse gets tiresome.
C. that kind of common language symbolizes their status in life.
D. it's the language of love.
The craftsmen in the play speak in prose because: that kind of common language symbolizes their status in life. Option C is correct.
I think that any craftsman would speak very posh and in a high register language of poetry, hence they speak in prose, which is not that classy.
Prose is a form of language that conveys a natural flow of speech and grammatical structure instead of a regular rhythmic structure as in traditional poetry.