Suppose, that P1, P2, and P3 are variables whose values are 1 if a particular plant is to be opened and 0 otherwise. Write a single linear constraint that reflects each of the following word constraints

A. If plant 1 is opened, then plant 2 must also be opened

B. not more than two of the three plants should be opened

C. if neither plant 2 nor plant 3 is opened, then plant 1 should not be opened

D. if plant 1 is opened or plant 3 is not opened, then plant 2 must be opened.