You Plan a Conference Call to Present Your New Marketing

You plan a conference call to present your new marketing proposal to two of your partners in China-Arthur Tang and Barbara Liu.You decide that the probability of Arthur endorsing the proposal is 0.6 and probability of Barbara endorsing the proposal is 0.4.The probability that both will endorse the proposal is put at 0.1.Determine the probability that Barbara will endorse your proposal given that Arthur does not.

A) .5
B) .25
C) .2
D) .75
E) .8