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

Problem: what is the probability of randomly selecting one of the shortest diagonals from all the diagonals of a regular hexagon ? 
Options: a ) 1 / 4 , b ) 1 / 3 , c ) 1 / 2 , d ) 2 / 3 , e ) 7 / 9
d