Fill in the blank.
_________are still tortured in remote villages.

The sentence requires a plural subject because it is followed by the plural auxiliary verb "are".
For compound nouns formed with a prepositional phrase attachment (like daughter-in-law), the rule for making the word plural is to append the '-s' suffix exclusively to the principal root word (which is the noun component "daughter"). Hence, the correct plural form is Daughters-in-law.