Hich is the correct possessive form of the compound noun mother-in-law needed to complete the sentence? my birthday is in may. a)mother’s-in-law b)mother-in-laws c)mother-in-laws' d)mother-in-law’s

D: mother-in-law's

Explanation:

 The correct possessive form of the compound noun mother-in-law to complete the sentence is made by adding an apostrophe and an "s" to it:   mother-in-law's. Only the last word is used to show possession when it is a singular compound word. In the case of plural, as in C, only the apostrophe is added to the "s" of the last word.