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]: 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

[EX Q]: Today there are ____ UK hospitals doing heart transplants.\Question: Choose the right answer from options given a) three b) five c) six d) nine
[EX A]: d

[EX Q]: Outer shells can hold more electrons but are considered stable when they contain ____ electrons.\Question: Choose the right answer from options given a) nine b) ten c) seven d) eight
[EX A]:
d