You have a project with four tasks as follows: Task 1 can start immediately and has an estimated duration of one. Task 2 can start after task 1 is completed and has an estimated duration of four. Task 3 can start after Task 2 is completed and has an estimated duration of five. Task 4 can start after Task 1 is completed and must be completed when Task 3 is completed. The estimate for Task 4 is ten. What is the shortest amount of time in which the project can be completed?
Answers :  
 A)10.0
 B)9.0
 C)18.0
 D)11.0