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').

Chlorine gives vinyl ____ advantages.\Question: Choose the right answer from options given a) six b) four c) two d) ten
c

Couples often date from one to ____ years before getting engaged.\Question: Choose the right answer from options given a) three b) nine c) eight d) seven
a

Most females can mate once every ____ or four years.\Question: Choose the right answer from options given a) four b) three c) six d) ten

b