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: Orangutans spend up to ____ hours a day eating or foraging for food.\Question: Choose the right answer from options given a) seven b) nine c) three d) six
Example Output: d

Example Input: Diarrheal disease kills ____ million children every year.\Question: Choose the right answer from options given a) three b) no c) four d) ten
Example Output: a

Example Input: Some protozoans have ____ means of movement.\Question: Choose the right answer from options given a) nine b) eight c) no d) five
Example Output:
c