Consider the following statements related to pore pressure parameters, $A$ and $B$:

1. $A$ always lies between $0$ and $1.0$
2. $A$ can be less than $0$ or greater than $1.0$
3. $B$ always lies between $0$ and $1.0$
4. $B$ can be less than $0$ or greater than $1.0$

For these statements, which of the following options is correct?

1. P and R
2. P and S
3. Q and R
4. Q and S