since the arp broadcast is utilized to request the mac address of the host with the ip address contained in the arp, the pc needs to know the destination of mac address before it can produce the frame header for the particular ping requested, before it can send a ping to a host.
the answer is c: both of the two students are correct.
voltage in very simple terms is what makes electric charges move. it is that push or force that causes charges to move in an electrical conductor. thus, student a is correct since voltage is a specific measure of potential energy that exists and is always relative between two points. on the other hand, power is the rate, per unit time, at which electrical energy travels. electrical power (p) is the product of both voltage and current and not either one separately. it is a function of voltage and current. thus, student b is also correct.