Which one of the following is active transport?

A. It is the movement of a substance against a diffusion gradient with the use of energy from respiration

B. It is the movement of a substance against a diffusion gradient without the use of energy

C. It is the movement of a substance against a diffusion gradient with the use of energy from photosynthesis

D. It is the movement of a substance along a diffusion gradient with the use of energy from respiration

Answer: Option A