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: Astronomical observations suggest ____ or close to zero space-time curvature.\Question: Choose the right answer from options given a) six b) zero c) ten d) seven

Output: b


Input: Consider Input: Mothers typically have from one to ____ cubs, which are born blind and toothless.\Question: Choose the right answer from options given a) six b) zero c) four d) seven

Output: a


Input: Consider Input: Hemorrhage is extremely uncommon in an eye which has had ____ previous surgery.\Question: Choose the right answer from options given a) seven b) no c) one d) eight


Output: b