The question says the machine uses up m gallons of oil each hour on weekends.
This means that if the machine works for 24 hours each day, it implies that:

There are only two days on weekends i.e. Saturday and Sunday.
This means that if the amount of oil used in 1 day in the weekend is 24m, then we can say:
Saturday: oil used is 24m
Sunday: oil used is 24m
Total oil used during the weekend is:
The answer is 2, yous add all of them up and divide by how many there are.
Answer:
b. n
d. 2^lgn
c. n^2.1
a. 4^2lgn
Step-by-step explanation:
Logarithm is a function of mathematics which is used to calculate inverse function of exponents. The asymptotically smallest function will be the one that has smallest or no exponents. The exponent function is calculated in reverse when log is applied. The function with highest exponents will be largest asymptotically.