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').

[Q]: Lung disease is America's number three killer, responsible for ____ in seven deaths.\Question: Choose the right answer from options given a) five b) nine c) one d) four
[A]: c


[Q]: Black widows mature in ____ to four months.\Question: Choose the right answer from options given a) two b) seven c) eight d) zero
[A]: a


[Q]: Asthma occurs in African-American children at ____ times the national rate.\Question: Choose the right answer from options given a) five b) three c) seven d) eight
[A]:
b