In the following circuit employing pass transistor logic, all NMOS transistors are identical with a threshold voltage of $1\: V.$ Ignoring the body-effect, the output voltage at $P,Q$ and $R$ are,
- $4\: V, 3\:V,2\:V$
- $5\: V, 5\:V,5\:V$
- $4\: V, 4\:V,4\:V$
- $5\: V, 4\:V,3\:V$