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]: Avian kidneys have ____ kinds of nephrons.\Question: Choose the right answer from options given a) four b) eight c) no d) two
[A]: d


[Q]: Baboons can travel up to ____ miles a day.\Question: Choose the right answer from options given a) seven b) three c) two d) six
[A]: d


[Q]: Milk proteins can cause colic, a digestive upset that bothers one in ____ infants.\Question: Choose the right answer from options given a) seven b) six c) no d) five
[A]:
d