请问此题该怎麽解？谢了。

If the probability is 0.54 that Stock A will increase in value during the next month and the probability is 0.68 that Stock B will increase in value during the next month, what is the greatest possible value for the probability that neither of these two events will occur?

A.     0.22

B.      0.32

C.     0.37

D.     0.46

E.     0.63

the answer is b