Answer:
them
Explanation:
It makes no grammatical sense for "it"
West Side Story is the honor winning adjustment of the great sentimental disaster, "Romeo and Juliet". The quarreling families end up noticeably two warring New York City posses the white Jets driven by Riff and the Puerto Rican Sharks, driven by Bernardo.
The linking verb is the word, "is" and "effective" is the predicate adjective.
I hope this helps.
Take care,
Diana
