Consider the following work breakdown structure:

$\backslash$table$[[$Activity$,$Precedes,$\backslash$table$[[$Duration Estimates $($Days$)],[$Optimistic$]],$Most Likely,Pessimistic$],[$Start$,$U$,$V$,-,-,-],[$U$,$W$,35,50,65],[$V$,$W$,$X$,28,40,52],[$W$,$Z$,26,35,44],[$X$,$Y$,28,40,52],[$Y$,$Z$,26,29,38],[$Z$,$End,$36,60,84]]$

What is the estimated expected $($mean$)$ time for project completion?

$135$ days

$145$ days

$170$ days

$180$ days

$255$ days