please assist:

[T] In a stochastic version of the \"Field of Dreams" the probability that historic baseball greats will appear (A) 8: playa game (G) on a baseball diamond carved {built} {B} from a corn field is P(G n A n B}. As if the following is the only improbable aspect of this event, suppose the probability that the baseball diamond is built is 0.4. Once it is there, the chance the historic baseball greats will appear is 0.2, and the chance they will choose to play after being there and surveying the field is 0.1. [a] What is the an: n A n a)