#### Answer

6 C
72 joules
power supplied by the battery

#### Work Step by Step

Voltage ,Vab,=-12V
Current , Iab, = 3 amp
We know that Charge flowing throw a point is = Current flowing x time
Q = 3x2=6 column
Vab = -12V
Iab = 3 amp
Power =-12x3=-36w
power is negative so energy is supplied by the battery.
when power is supplied by the battery Vab is negative it means point b is at higher potential .
therefore, current will flow from b to a and electrons flow opposite to conventional direction from A to B . Hence electrons will enter b point