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').

Input: Consider Input: Water weighs about ____ pounds per gallon.\Question: Choose the right answer from options given a) seven b) ten c) zero d) nine

Output: b


Input: Consider Input: Parapsychologists have ____ basic approaches to their subject matter.\Question: Choose the right answer from options given a) three b) two c) ten d) five

Output: b


Input: Consider Input: Malaria is caused by ____ protozoan parasite species in the genus Plasmodium.\Question: Choose the right answer from options given a) three b) zero c) seven d) four


Output: d