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:
Dogs are pack animals, and ____ dogs is the minimum number for proper socialization.\Question: Choose the right answer from options given a) four b) five c) no d) zero

Ex Output:
b


Ex Input:
Hamsters can live to be three to ____ years old.\Question: Choose the right answer from options given a) four b) two c) three d) nine

Ex Output:
a


Ex Input:
Some infections have ____ obvious symptoms.\Question: Choose the right answer from options given a) one b) two c) no d) six

Ex Output:

c