The units of volume charge density are

Coulomb/meter
Coulomb/meter2
Coulomb/meter3
Coulomb/meter4

The correct answer is C. Coulomb/meter3.

Charge density is the amount of electric charge per unit volume. The SI unit of charge is the coulomb (C), and the SI unit of volume is the cubic meter (m3). Therefore, the units of charge density are C/m3.

Option A, Coulomb/meter, is the unit of linear charge density. Linear charge density is the amount of electric charge per unit length.

Option B, Coulomb/meter2, is the unit of surface charge density. Surface charge density is the amount of electric charge per unit area.

Option D, Coulomb/meter4, is not a valid unit.