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').

Example Input: Summer is the hottest of the ____ temperate seasons , falling between spring and autumn .\Question: Choose the right answer from options given a) six b) four c) no d) nine
Example Output: b

Example Input: Parliamentary democracy is less than ____ years old in Nigeria.\Question: Choose the right answer from options given a) eight b) two c) nine d) three
Example Output: b

Example Input: Reservoirs cover an area of the planet ____ times the size of Britain.\Question: Choose the right answer from options given a) two b) eight c) three d) six
Example Output:
d