Life processes and types of nutrition

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

(Choice A)
Diffusion is a slow process that cannot efficiently transport oxygen over long distances.
(Choice B)
Diffusion can only occur in single-celled organisms.
(Choice C)
Multi-cellular organisms do not require oxygen for their metabolic processes.
(Choice D)
Diffusion is an energy-intensive process that can harm the cells of multi-cellular organisms.

Bridge Course Class 11th Biology