Which of the following are examples of allotropes?
(A) CO, CO2, CO3
(B) V2+, V3+, V4+
(C) Graphite, diamond, fullerene
(D) Red phosphorus, white phosphorus
(E) Ice, water, steam
Allotropism is a property of chemical elements that describe the ability to exist in two or more forms due to differences in bonding between atoms, resulting in having different properties. Only options C and D describe this behavior (differences in carbon-carbon and phosphorus-phosphorus bonding respectively).