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: All mass spectrometers consist of ____ distinct regions.\Question: Choose the right answer from options given a) three b) one c) two d) zero

Output: a


Input: Consider Input: Polyester has ____ favorable properties.\Question: Choose the right answer from options given a) four b) two c) seven d) six

Output: b


Input: Consider Input: Pelagic division is divided into neritic and ____ levels of pelagic provinces.\Question: Choose the right answer from options given a) three b) six c) nine d) ten


Output: a