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: Cigarette smokers are ____ times more likely to die of lung cancer than nonsmokers.\Question: Choose the right answer from options given a) ten b) six c) four d) nine
Example Output: a

Example Input: Elephants have four molars, which are replaced ____ times, for a total of six sets in a lifetime.\Question: Choose the right answer from options given a) five b) no c) three d) one
Example Output: a

Example Input: Larger spikelets can have ____ to four florets.\Question: Choose the right answer from options given a) no b) four c) three d) six
Example Output:
c