Answer:
3rd and 4th options are correct that is 24 hours per day and 7 days per week.
Step-by-step explanation:
We need to find the conversion factors that can be used to find number of hours in a week.
We know that,
Number of hours in a day = 24
and
Number of days in a week = 7
So, Number of hours in 7 days = 24 × 7 = 168.
Therefore, 3rd and 4th options are correct that is 24 hours per day and 7 days per week.