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: Cougars have ____ toes with three distinct lobes present at the base of the pad.\Question: Choose the right answer from options given a) no b) four c) eight d) zero
Example Output: b

Example Input: Bats actually echolocate using ____ different systems, depending on the species of bat.\Question: Choose the right answer from options given a) one b) six c) two d) three
Example Output:
d