Problem $3.$ A$3\mathrm{.}8-$uF capacitor is connected in series with two $2\mathrm{.}2-$kS resistors and a $12\mathrm{.}0-$V source.

$8.$ Which of the following diagrams represent the equivalent circuit? $($A$)$

$($B$)$

$($C$)$

$($D$)$

$($E$)$

$9.$ What is the time constant $\backslash (\backslash$tau $\backslash )$ of the equivalent circuit?

$($A$)1$ min

$($B$)17$ ms

$($C$)35$ ms

$($D$)52$ ms

$($E$)2$ ms

$10.$ Starting from the uncharged state, how long does it take for the current to drop from its initial value to $1\mathrm{.}35$ mA $?$

$($A$)1$ min

$($B$)10$ min

$($C$)12$ ms

$($D$)42$ ms

$($E$)25$ ms