Correct option is D
Let's analyze the given words:
Second – A unit of time.
Minute – A unit of time (60 seconds).
Hour – A unit of time (60 minutes).
Time – A general concept, not a specific unit.
So, Second, Minute, and Hour are all specific units of time measurement. But, Time is a broader concept and not a specific unit.
Thus, the correct option is: (d)