Owning provides flexibility but can lead to costs in the long term

a-greater ; lower
b- greater; higher
c- less; lower
d- less; higher

This problem depends on a few variables, such as long term rental growth rates and interest rates, but generally, the answer is: 

C) Owning provides less flexibility but can lead to lower costs in the long term.

Owning eliminates the periodic expense that comes with renting something, aside from the interest paid if money is lent for the purchase. Even in the case of paying a mortgage or some form of monthly payment to pay down the purchased item, you have the guarantee that you will pay the same amount every period, while the cost of renting something can fluctuate. 
 
It is, however, less flexible to own rather than rent. There are more costs and inconveniences associated with selling property than with terminating a lease, and in the case of an asset that depreciates, there can be a significant loss on resale that makes selling even more costly. 

$80,000

Explanation:

Calculation to determine the amount of differential revenue

Using this formula

Differential revenue=Per units*Number of units

Let plug in the formula

Differential revenue=$400 x 200 units

Differential revenue= $80,000

Therefore the amount of differential revenue is $80,000