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: Earthworms have ____ pairs of hearts.\Question: Choose the right answer from options given a) seven b) five c) one d) no
Example Output: b

Example Input: Lines of force are ____ dimensional, surrounding a bar magnet on all sides.\Question: Choose the right answer from options given a) eight b) three c) zero d) no
Example Output: b

Example Input: Deep marshes have water up to ____ feet deep.\Question: Choose the right answer from options given a) zero b) six c) no d) three
Example Output:
d