American ______ efforts helped win the war. Is it

A. soldiers
B. soldier's
C. soldiers'
D. soldiers's

C. soldiers'

It's both plural and possessive.

To determine the correct answer for the phrase "American ______ efforts helped win the war," we need to consider the possessive form of the noun "soldiers."

The possessive form indicates ownership or possession. In this case, we are referring to the efforts' ownership or belongingness to the soldiers. The rules for forming the possessive form of a noun depend on whether the noun is singular or plural.

Now, let's analyze each option:

A. "soldiers" - This is the plural form of the noun without any possessive indication.

B. "soldier's" - This is the singular possessive form of the noun. It would indicate the efforts of one soldier.

C. "soldiers'" - This is the plural possessive form of the noun. It would indicate the efforts of multiple soldiers.

D. "soldiers's" - This is an incorrect form of the noun, as adding an additional "s" to the plural form is unnecessary.

Considering the context of the sentence, where we are discussing the efforts of multiple American soldiers, the correct answer is C. "soldiers'" since it shows ownership or possession by the plural noun.

Therefore, the correct phrase is "American soldiers' efforts helped win the war."