Determine whether 4B is defined. If it is defined, express the result as a single matrix; if it is not, say "not defined.\" 02 -1 31 0 A= . B= 12 5 -6 6 -5 Select the correct choice below and, if necessary, fill in the answer bax to complete your choice. (O A. The expression 4B is defined. 4B = () B. The expression 4B is not defined