ANS:B - Effective time

Access time is related to the time taken to access a piece of information from the memory, let it the RAM or anything else.

Seek time is related to the Storage Disks. It is the time taken by the head to get to the required position from the current position in order to read the data.

I don't know the exact meaning of the Real Time, but according to what I read, real time is relative to the user than any system. If a user requests for any service, in what time does it get serviced is Real Time.

So, Effective Time make more sense here. Given an equipment that you are working on, how long will it work for is its effective usage time.