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: Tardigrades are microscopic, water-dwelling, segmented animals with ____ legs.\Question: Choose the right answer from options given a) eight b) nine c) one d) seven
Example Output: a

Example Input: Evolution is dependent on ____ forces.\Question: Choose the right answer from options given a) no b) five c) two d) seven
Example Output: c

Example Input: Essential oils enter the body in ____ ways.\Question: Choose the right answer from options given a) two b) three c) ten d) zero
Example Output:
b