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: Brachiopods are superficially similar to bivalves, both having ____ shells.\Question: Choose the right answer from options given a) two b) eight c) seven d) one

Output: a


Input: Consider Input: Black bears stand ____ to six feet long and almost three feet at the shoulders when on all fours.\Question: Choose the right answer from options given a) three b) five c) four d) one

Output: b


Input: Consider Input: Arms also have ____ kinds, hollow and solid forms.\Question: Choose the right answer from options given a) seven b) no c) two d) ten


Output: c