Q: 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 tails ? 
Options: a ) 1 / 5 , b ) 1 / 7 , c ) 1 / 8 , d ) 1 / 2 , e ) 1 / 10
A:
d