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]: Cigarette smokers are ____ times more likely to die of lung cancer than nonsmokers.\Question: Choose the right answer from options given a) ten b) six c) four d) nine
[EX A]: a

[EX Q]: Most children improve in three to ____ days.\Question: Choose the right answer from options given a) seven b) six c) four d) ten
[EX A]: a

[EX Q]: Midrange drivers are used in multi-way speakers with ____ or more driver sizes.\Question: Choose the right answer from options given a) one b) five c) four d) three
[EX A]:
d