When air is heated enough so that it is warmer than the surrounding air, it is?

To be "unstable", the lowest layers of an air mass must be so warm and/or humid that, if some of the airrises, then that air parcel is warmer than its environment, and so it continues to rise. This is called moist convection.

The answer is Unstable air

Your answer is c. explanation: plasma  is the fourth state of matter, derived from the gaseous state of matter.  plasma  can contain free  electrons  and/or  ions. while  plasma is never neutral, it can either be positively or negatively charged.  gases, however, are electrically neutral.