What is not a feature of tasks in Salesforce?

Answer options:

A.You can set tasks to be recurring
B.You can set a start and end time
C.You can access tasks on Salesforce1
D.Tasks can be automatically created

Correct Answer: B 
You can’t set a start and end time. Not even with the standard salesforce functionality. The due date field has a timestamp that is always set to midnight in the Coordinated Universal Time (UTC) time zone. The timestamp is not relevant; do not attempt to alter it to accommodate time zone differences. A label is a Due Date. 
Options A, C & D are incorrect because they specify the task features. 
Reference: 

https://success.salesforce.com/ideaView?id=08730000000J5oj