If a is the optimistic time, b is the pessimistic time and m is most likely time of an activity, the expected time of the activity, is

• A. <img src="/_files/images/civil-engineering/construction-management/74-19-74-1.png">
• B. <img src="/_files/images/civil-engineering/construction-management/74-19-74-2.png">
• C. <img src="/_files/images/civil-engineering/construction-management/74-19-74-3.png">
• D. <img src="/_files/images/civil-engineering/construction-management/74-19-74-4.png">