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:
Teething begins for most babies around ____ to six months.\Question: Choose the right answer from options given a) three b) four c) five d) seven

Ex Output:
b


Ex Input:
Many scientists believe the neutrino has ____ mass at all.\Question: Choose the right answer from options given a) eight b) zero c) two d) no

Ex Output:
d


Ex Input:
All societies share ____ cultural universals.\Question: Choose the right answer from options given a) eight b) four c) seven d) six

Ex Output:

c