Q$4)$ The circuit in Figure $4($a$)$ is simplified to the circuit in Figure $($b$)$ using source transformation. The values of the current source $(i)$ and the resistanco $R_{eq.}.$ espectively, are:

A$)3mA,25k$

B$)1mA,12\mathrm{.}5k$

C$)2mA,50kI.$

D$)-1mA,25k$

$($E$)-4mA,12\mathrm{.}5k$

Fig$\mathrm{.}4($a$)$

Fig$\mathrm{.}4($b$)$