【单选题】

For an activity，the optimistic，most likely and pessimistic estimates are 12，16 and 18 respectively．Which of the following statement is correct
A．There is 68.26% chance that the activity will be completed in 15 to 17 day

B．There is 95.44% chance that the activity will be completed in 15 to 17 day
C．There is 68.26% chance that the activity will be completed in 14.67 to 16.67 day
D．There is 93.73% chance that the activity will be completed in 15 to 17 day