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]: Chlorine is manufactured in ____ ways.\Question: Choose the right answer from options given a) four b) two c) nine d) seven
[EX A]: b

[EX Q]: Pups remain in the den for about ____ weeks, and are cared for by the entire pack.\Question: Choose the right answer from options given a) ten b) three c) six d) no
[EX A]: c

[EX Q]: Tubes generally stay in place for one to ____ months and fall out on their own.\Question: Choose the right answer from options given a) seven b) three c) zero d) eight
[EX A]:
b