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').

Q: Malignant tumors are more dangerous, and survival times can range from ____ months to several years.\Question: Choose the right answer from options given a) one b) no c) ten d) six

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

A: b
****
Q: Complete darkness is only possible at absolute ____ .\Question: Choose the right answer from options given a) two b) five c) six d) zero

A:
d
****