Consider a source-less 3-D steady-state diffusion problem. The general discretized equation is aP ΦP = ∑anb Φnb. What is aP?

Consider a source-less 3-D steady-state diffusion problem. The general

1.	Consider a source-less 3-D steady-state diffusion problem. The general discretized equation is aP ΦP = ∑anb Φnb. What is aP?
A.	aP=aW+aE+aS+aN+aT+aB
B.	aP=aW+aE+aS+aN
C.	aP=aW+aE+aS+aN+aT
D.	aP=0
Answer» B.