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: Real airplanes have round engines and ____ wings.\Question: Choose the right answer from options given a) four b) six c) three d) two

Output: d


Input: Consider Input: Batteries consist of ____ electrodes immersed in an electrolyte.\Question: Choose the right answer from options given a) two b) eight c) three d) seven

Output: a


Input: Consider Input: Hubs have a heirarchial topology, with a root hub, that can branch ____ deep in the heirarchy.\Question: Choose the right answer from options given a) three b) nine c) seven d) ten


Output: a