Continental Polar (CP)and Continental Arctic (CA)air Masses

Continental polar (cP) and continental Arctic (cA) air masses

A) both originate over polar oceans.
B) form in summer only.
C) originate over the ice- and snow-covered regions of the Arctic, northern Canada, and Alaska where long, clear nights allow for strong radiational cooling of the surface.
D) bring strong thunderstorms.
E) produce wet weather and temperatures around the freezing point.