An ongoing project requires several parts manufactured at an outside vendor. If the vendor has sufficient quantity and can still ship today, the parts should be received in five days; although in most cases an order of this size requires ten days. Allowing for an upcoming holiday and some potential bad weather the shipment could take up to twenty-one days. Using the PERT method, which of the following is the correct time estimate for a parts delivery?
A.
10 days
B.
11 days
C.
21 days
D.
36 days