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: Some people have ____ symptoms until the liver has been quite severely damaged.\Question: Choose the right answer from options given a) eight b) no c) nine d) ten
Example Output: b

Example Input: China is reportedly in the top ____ nations in industrial output.\Question: Choose the right answer from options given a) seven b) ten c) three d) five
Example Output: b

Example Input: All insects lay eggs, and most go through ____ stages of metamorphosis.\Question: Choose the right answer from options given a) four b) one c) eight d) seven
Example Output:
a