In the frog Markov chain, if the current distribution is p2 = 0.25, p3 = 0.25, p4 = 0.5, what is the probability distribution in the next period?

A. p2 = 0.25, p3 = 0.25, p4 = 0.5
B. p2 = 0.125, p3 = 0.375, p4 = 0.5
C. p2 = 0.1875, p3 = 0.1875, p4 = 0.625
D. p2 = 0.3125, p3 = 0.3125, p4 = 0.375