Question: 45 (Choose 1 answer)
The sizes of two matrices A and B are 2\times1 and 1\times1, respectively. Find the sizes of the products AB and BA,if they are defined.
A. AB is 2\times1 BA is undefined.
B. AB is 2\times2 BA is 1\times1.
C. AB is undefined, BA is 1\times2.
D. AB is 1\times2, BA is 1\times1.
E. None of the other choices is correct
