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:
Tetrapods are animals that have ____ legs or leg-like appendages.\Question: Choose the right answer from options given a) four b) one c) ten d) six

Ex Output:
a


Ex Input:
Most women take about ____ weeks to stop bleeding and to heal inside.\Question: Choose the right answer from options given a) two b) no c) four d) zero

Ex Output:
c


Ex Input:
Atherosclerotic plaques cause clinical disease by ____ mechanisms.\Question: Choose the right answer from options given a) three b) two c) no d) zero

Ex Output:

a