Find the Products AB and BA to Determine Whether B

Find the products AB and BA to determine whether B is the multiplicative inverse of A.
- $A = \left[ \begin{array} { r r } - 5 & - 1 \\ 6 & 0 \end{array} \right] , \quad B = \left[ \begin{array} { c } 0 \frac { 1 } { 6 } \\ - 1 \frac { 5 } { 6 } \end{array} \right]$

A) $B \neq A ^ { - 1 }$
B) $B = A ^ { - 1 }$