B) As shown in the figure, the voltage across the resistor = 15V, and the current flowing through it =3A. From the current direction, it is obvious that the current source provides 2A, so the voltage source provides1a.. Power is calculated by yourself;

Similarly, in the figure, the voltage across c) resistor = 15V, and the current flowing through it =3A. Judging from the current direction, the voltage source outputs 5A current, and the current source absorbs power.

In fact, these two problems can be clearly understood by node current method;