What type of relationship does the law of demand demonstrate?

Suppose Arf n' Barf restaurant has a monopoly on restaurant food in a certain small town. Their rent, which is one of several fixed costs they pay whether they sell food or not, has gone up. In the short run, the Arf n' Barf should

a. pay the higher rent and increase menu prices b. pay the higher rent and leave menu prices unchanged c. pay the higher rent and lower prices d. go out of business e. shut down

Refer to the diagram, in which C 1 is the before-tax consumption schedule. Other things being equal, the economy would enjoy the greatest built-in stability with consumption schedule:

A.  C 1 .
B.  C 2 .
C.  C 3 .
D.  C 4 .