In this task, you need to provide the correct option for a given problem on probability from the provided options.

Input: Consider Input: Problem: if a coin has an equal probability of landing heads up or tails up each time it is flipped , what is the probability that the coin will land heads up exactly once in 3 consecutive flips ? 
Options: a ) 0.125 , b ) 0.25 , c ) 0.75 , d ) 0.375 , e ) 0.666

Output: d


Input: Consider Input: Problem: if a certain coin is flipped , the probability that the coin will land heads is 1 / 2 . if the coin is flipped 5 times , what is the probability that it will land heads up on the first 4 flips but not on the last flip ? 
Options: a ) 1 / 2 , b ) 1 / 4 , c ) 1 / 8 , d ) 1 / 16 , e ) 1 / 32

Output: e


Input: Consider Input: Problem: what is the probability of getting only 1 head in a single throw of four fair coins ? 
Options: a ) 1 / 2 , b ) 3 / 8 , c ) 1 / 4 , d ) 1 / 5 , e ) 5 / 8


Output: c