Answer
a) No
b) No
c) Yes, No
Work Step by Step
a) Since $A, B$ do not have the same order (same dimensions), they cannot be equal.
b) No. For addition of two matrices to be defined, they must be of the same order.
c) $AB$ is defined as the number of columns of $A$ is equal to the number of rows of $A$.
However, $AB=BA$ is not possible, because for this to happen, first $BA$, must be defined, which in this case is not true. This is because the number of columns of $B$ is not equal to the number of rows of $A$.
