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').

Input: Consider Input: Reverse osmosis uses three to ____ gallons of water to produce one gallon of drinking water.\Question: Choose the right answer from options given a) six b) eight c) five d) ten

Output: d


Input: Consider Input: Sea stars have ____ arms, or rays, connected to a small round body.\Question: Choose the right answer from options given a) five b) six c) seven d) no

Output: a


Input: Consider Input: Special relativity shows that time behaves surprisingly like the ____ spatial dimensions.\Question: Choose the right answer from options given a) three b) five c) eight d) one


Output: a