Select the correct answer. what is the si unit of time? a. second b. minute c. hour d. day

Option A: second

SI units are international system of units. This is defined as a system of units of physical quantities such as mass, length, temperature, current etc. Some of the physical units are gram, meter, second etc. along with the set of prefixes which indicates the multiplication and division with some power of 10.

For same physical quantities, these units are inter convertible For example,

and,

Here, g (gram), kg (kilogram) and mg (milligram) all are units of mass.

The units of time are second, minute, hour, day and year. Here, second is the SI unit and all the units are inter convertible as  follows:

1 year=365 days

1 day=24 hours

1 hour=60 minutes

1 minute-60 seconds

Thus, the SI unit of time is second.