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]: Hummingbirds feed every ____ to fifteen minutes from sun-up to sundown.\Question: Choose the right answer from options given a) nine b) seven c) four d) ten
[EX A]: d

[EX Q]: Most volcanoes erupt for ____ to four weeks and then rest.\Question: Choose the right answer from options given a) three b) four c) one d) eight
[EX A]: a

[EX Q]: Most people resort to food, although smokers only gain about ____ pounds on average when they quit.\Question: Choose the right answer from options given a) six b) two c) one d) five
[EX A]:
d