60 / 5 = 12 miles per gallon
36 miles = 12 miles / gal * x gallons
divide by 12
36/12 =x gallons
3 =x
He needs 3 gallons
Solution: We are given the population mean 
Now, in order to find which shift's mean is closest to population mean, we will find the mean of each shift.
The mean of shift 1 is:

The mean of shift 2 is:

The mean of shift 3 is:

The mean of shift 4 is:

We clearly see the mean of shift 2 is close to the population mean. Hence the option B) Shift 2 is correct.
Answer: The correct option is c.
Explanation:
Reason for correct option:

This expression cannot be factored further because
is the complete factor. Therefore the option c is correct.
Reason for incorrect option:

Since the given expression can be factored further therefore the option d is incorrect.

Since the given expression can be factored further. Therefore the option a is incorrect.

Since the given expression can be factored further. Therefore the option b is incorrect.