Which physical property do plasmas and gases have in common? a. they both have charged particles b. they have the same attractive forces between particles c. they have the same space between particles d. they create magnetic and electric fields

The correct option is C. 
Plasma refers to a gas that has been heated to the point of ionization, that is, almost all the electrons in the atoms of the gas have been removed and only proton exist as positively charged particles. 
Plasma has properties that differs from that of gases but the space between the particles of plasma and that of gases are the same.