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').

Example Input: Redwoods reproduce ____ ways.\Question: Choose the right answer from options given a) zero b) two c) six d) nine
Example Output: b

Example Input: Most aphthous ulcers heal in one to ____ weeks.\Question: Choose the right answer from options given a) two b) eight c) one d) seven
Example Output: a

Example Input: Most logic gates have ____ inputs and one output.\Question: Choose the right answer from options given a) no b) two c) eight d) three
Example Output:
b