Write the Word or Phrase That Best Completes Each Statement $A = \left[ \begin{array} { l l } d & 0 \\ 0 & f \end{array} \right]$

Multiple Choice

Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
-Let $A = \left[ \begin{array} { l l } d & 0 \\ 0 & f \end{array} \right]$ , where $d$ and $f$ are nonzero constants. Find $A ^ { - 1 }$ .

A)
$\left[ \begin{array} { l l } \frac { 1 } { \mathrm {~d} } & 0 \\ 0 & \frac { 1 } { \mathrm { f } } \end{array} \right]$
B)
$\left[ \begin{array} { l l } \mathrm { d } & 0 \\ 0 & \mathrm { f } \end{array} \right]$
C)
$\left[ \begin{array} { l l } 0 & d \\ f & 0 \end{array} \right]$
D)
$\left[ \begin{array} { l l } \frac { 1 } { d } & 1 \\ 1 & \frac { 1 } { f } \end{array} \right]$