What is the correct way to write the quotation part of the sentence?

My "mother-in-laws" blueberry pie won first place at the county fair.

A - mother-in-laws'

B - mother's-in-law

C - mother-in-law's

D - mothers'-in-law

The correct way to write the quotation part of the sentence is: mother-in-law's. The correct answer is option C. The sentence would be written like this: My mother-in-law's blueberry pie won first place at the county fair. We used the 's because it shows ownership or possession. The blueberry pie is owned by the mother-in-law.