Poisons like cyanide inhibit `Na^(+)` influx during cellular transport. This inhibitory effect is reversed by an injection of ATP. This demonstrates that
A. `Na^(+) - K^(+)` pump operates fully in cells
B. ATP is hydrolysed by ATPase to release energy
C. Energy for `Na^(+)- K^(+)` pump comes from ATP hydrolysis
D. ATP is a carrier protein
