A project has four major activities. Activity A precedes activity B, activity C precedes activity D. 3-point estimates for activities are A(7.5, 15, 22.5 ), B( 4, 8, 12 ), C( 2, 4, 6 ), D( 9.5, 19, 28.5 ) weeks. What probability would you assign to a project duration of more than 23 weeks?
Select one:
a. 0.75
b. 0.861
c. 0.5
d. 0.388