Given a sentence with a missing word, pick the answer option that best fills out the missing word in the sentence. Indicate each answer with its index ('a', 'b', 'c', 'd').

Ex Input:
Electrons have almost ____ mass and are negatively charged.\Question: Choose the right answer from options given a) three b) seven c) zero d) no

Ex Output:
d


Ex Input:
Granite occurs in ____ separate masses.\Question: Choose the right answer from options given a) two b) eight c) nine d) no

Ex Output:
a


Ex Input:
Genetic manipulation is of ____ kinds.\Question: Choose the right answer from options given a) two b) zero c) three d) seven

Ex Output:

a