Using the following matrices, evaluate if possible ...

Using the following matrices, evaluate if possible
 

A=[2,0,]
1,3
 

B=[0,5]
2,1
0,3
1,0
 

C=[8,1,0,1]
0,2,3,1
 

D=[4,5,0,2]
0,1,3,0
1,2,1,2
5,0,1,4
 

1. BA
2. CD