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: Turkey also has ____ inland drainage basins.\Question: Choose the right answer from options given a) zero b) two c) eight d) nine
Example Output: b

Example Input: Circles mark the approximate locations of ____ recently discovered solar systems.\Question: Choose the right answer from options given a) four b) no c) zero d) nine
Example Output: a

Example Input: Seasoned wood means it has been cut and kept under cover for at least ____ months.\Question: Choose the right answer from options given a) two b) zero c) six d) one
Example Output:
c