Correct statement A. less reactive element displaces more reactive element

B. a non-metal displaces more reactive non metal

C. more reactive element displaces less reactive element

D. evolution of heat when carbon is burnt in air

Chemical displacement is a reaction in which more reactive element displaces the less reactive element from their compounds and form a new compound itself.

For example:

Zn + 2HCl → ZnCl₂ + H₂

In the reaction, zinc (being more reactive) has displaced hydrogen from HCl and form a new compound, i.e., ZnCl₂.