$\begin{bmatrix$}[r] 7 & -4 \ 3 & 8 \end{bmatrix} = \begin{bmatrix}[r] p & q \ r & s \end{bmatrix}\begin{bmatrix}[r] 1 & 0 \ 0 & 1 \end{bmatrix}, the values of p, q, r and s are respectively :

1. p = 7, q = 3, r = -4 and s = 8

2. p = 7, q = -4, r = 3 and s = 8

3. p = -4, q = 7, r = 8 and s = 3

4. p = 3, q = 8, r = 7 and s = -4

Given,

$\Rightarrow \begin{bmatrix$}[r] 7 & -4 \ 3 & 8 \end{bmatrix} = \begin{bmatrix}[r] p & q \ r & s \end{bmatrix}\begin{bmatrix}[r] 1 & 0 \ 0 & 1 \end{bmatrix} \\[1em] \Rightarrow \begin{bmatrix}[r] 7 & -4 \ 3 & 8 \end{bmatrix} = \begin{bmatrix}[r] p \times 1 + q \times 0 & p \times 0 + q \times 1 \ r \times 1 + s \times 0 & r \times 0 + s \times 1 \end{bmatrix} \\[1em] \Rightarrow \begin{bmatrix}[r] 7 & -4 \ 3 & 8 \end{bmatrix} = \begin{bmatrix}[r] p & q \ r & s \end{bmatrix}.

∴ p = 7, q = -4, r = 3 and s = 8.

Hence, Option 2 is the correct option.