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: Casinos have no windows and they have ____ clocks.\Question: Choose the right answer from options given a) six b) four c) eight d) no
Example Output: d

Example Input: Microwave ovens emit ____ kinds of radiation.\Question: Choose the right answer from options given a) six b) two c) four d) eight
Example Output: b

Example Input: Most black widows live only ____ year, but they can live up to three years.\Question: Choose the right answer from options given a) one b) two c) six d) seven
Example Output:
a