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:
Calves can browse and follow their mother at three weeks old and are weaned at ____ months.\Question: Choose the right answer from options given a) five b) seven c) four d) three

Ex Output:
a


Ex Input:
Giraffes sleep less than ____ hours a day.\Question: Choose the right answer from options given a) two b) six c) seven d) ten

Ex Output:
a


Ex Input:
Sexual reproduction is varied in ____ ways.\Question: Choose the right answer from options given a) seven b) two c) five d) three

Ex Output:

d