A project manager for Durable Construction Co. is about to build a house involving the following six activities: DURATION ESTIMATES days) ACTIVITY PRECEDES OPTIMISTIC MOST LIKELY PESSIMISTIC Start B c D E F AB CD D E F F End 45 42 31 27 58 50 60 45 40 36 70 56 75 48 49 39 82 What is the estimated expected (mean) duration for project completion? Select one: . 300 days Ob 160 days Oc210 days Od 200 days O e 170 days