Open circuit and Short circuit

Q. With sources $i_{A}and{V}_B$ are on in the circuit given below then$V_C=0,i_x=20A$, and when sources $i_{A}and{V}_C$ are on then $V_B=0,i_x=-5$ and finally, with all three sources on, $i_x=12A.$ If the the only source $V_B$ is operating, then the value of $i_x$ is

1. 17 A
2. -8 A
3. 32 A
4. 7 A