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 Q]: Heme is made of ____ pyrrole groups united to form a porphyrin ring.\Question: Choose the right answer from options given a) five b) four c) eight d) six
[EX A]: b

[EX Q]: Pups get their sight in about ____ days.\Question: Choose the right answer from options given a) five b) six c) ten d) nine
[EX A]: c

[EX Q]: Female tigers have a litter about once every ____ years.\Question: Choose the right answer from options given a) one b) two c) zero d) ten
[EX A]:
b