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:
Asthma accounts for ____ in six of all pediatric emergency visits in the United States.\Question: Choose the right answer from options given a) four b) seven c) one d) six

Ex Output:
c


Ex Input:
Females can only have four babies at ____ time.\Question: Choose the right answer from options given a) no b) one c) nine d) three

Ex Output:
b


Ex Input:
Echidnas are classified into ____ genera .\Question: Choose the right answer from options given a) zero b) five c) six d) three

Ex Output:

d