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]: Nymphs feed and mature through ____ instars in about six to eight weeks.\Question: Choose the right answer from options given a) four b) eight c) five d) no
[EX A]: c

[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]: Birds have one beak, two wings, and ____ feet.\Question: Choose the right answer from options given a) two b) ten c) zero d) five
[EX A]:
a