You will be given a definition of a task first, then some input of the task.
In this task, you need to provide the correct option for a given problem on probability from the provided options.

Problem: three unbiased coins are tossed . what is the probability of getting at least 2 heads ? 
Options: a ) 1 / 4 , b ) 1 / 2 , c ) 1 / 3 , d ) 1 / 8 , e ) 1 / 6
Output:
b