Consider the following work breakdown structure:

$\backslash$table$[[,$Start,Finish,$\backslash$table$[[$Duration $($days$)],[$Activity$]],$Node,Node,Optimistic,Most Likely,Pessimistic$],[$A$,1,2,41,50,59,,,,,,,],[$B$,1,3,54,60,66,,,,,,,],[$C$,2,4,58,70,82,,,,,,,],[$D$,3,4,32,41,44,,,,,,,]]$

What is the estimated standard deviation in the time for activity $D?$