Explain alternating current and direct current. include two ways that they are alike and one way that they are different.

Alternating current is an electric current which periodically reverses direction, in contrast to direct current which flows only in one direction. They are alike because you use watts to measure both AC and DC power, where one watt equals one joule per second and AC and DC electricity respond in the same manner to resistance. One way they are different is the direction of the flow DC is constant and moves in one direction while AC goes back and forth just like the name suggest.

d is the correct answer

if they have a finite resultant