Question

8. Which of the following is a unit of time?
a. Microsecond b. Century
c. Millennium d. all of these​

Answer 1

Explanation:

Here, hour, nano second and microsecond are all the unit of time. 

1 hour =3600 second, one nano second =109 second, one microsecond =10−6 second

Light year is the unit of astronomical distance and it is equivalent to distance traveled by light in one year.  

Answer 2

Answer:

unit of time is microseconds