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').

[EX 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
[EX A]: d

[EX Q]: Bacteria come in ____ basic shapes.\Question: Choose the right answer from options given a) five b) one c) three d) nine
[EX A]: c

[EX Q]: Nymphs progress through ____ nymphal instars.\Question: Choose the right answer from options given a) five b) zero c) no d) seven
[EX A]:
a