While Gardening,Greg Tripped Over a Coil of Wound-Up Hose and Fell

While gardening,Greg tripped over a coil of wound-up hose and fell face first on the pavement.He suffered damage to the hippocampal region in his brain.While recovering in the hospital,he consistently greeted his friends and family as though he saw them again after ages,even though he had met them the previous night.He often forgot what he did during the day.However,he could still recall adventures from his teenage years without effort.Greg MOST likely has:

A) retrograde amnesia.
B) anterograde amnesia.
C) long-term potentiation.
D) short-term potentiation.