Assume the sample space S = {win, loss}. Select the choice that fulfills the requirements of the definition of probability.

A. P{{win}} = 0.7, P{{loss}} = 0.2
B. P{{win}} = 0.7. P{{loss}} = 0.3
C P{{win}} = 1.0, P{{loss}} = 0.1
D. P{{win}} = 0.5, P{{loss}} = -0.5