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:
Elephants give birth to one calf every ____ to nine years on average.\Question: Choose the right answer from options given a) no b) four c) three d) seven

Ex Output:
b


Ex Input:
Mosquitoes have three body parts and ____ legs.\Question: Choose the right answer from options given a) two b) nine c) six d) eight

Ex Output:
c


Ex Input:
Every week has ____ days, seven days, seven days.\Question: Choose the right answer from options given a) nine b) no c) one d) seven

Ex Output:

d