Given the task definition and input, reply with output. In this task, you need to provide the correct option for a given problem from the provided options.

Problem: of the 20 members of a kitchen crew , 17 can use the meat - cutting machine , 18 can use the bread - slicing machine , and 15 can use both machines . if one member is chosen at random , what is the probability that the member chosen will be someone who can not use either machine ?
Options: a ) 0 , b ) 1 / 10 , c ) 1 / 7 , d ) 1 / 4 , e ) 1 / 3
a