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').

Q: Prairie dogs bear four or ____ young per litter.\Question: Choose the right answer from options given a) five b) eight c) two d) zero

A: a
****
Q: Elk retain their antlers for more than ____ months of the year.\Question: Choose the right answer from options given a) nine b) ten c) six d) seven

A: c
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Q: Many computers currently use ____ digits to record the year.\Question: Choose the right answer from options given a) six b) three c) one d) two

A:
d
****