for diffusion to occur, which condition must be met?\no a concentration gradient must exist.\no a hypotonic…

Brief Explanations:

Diffusion is the movement of substances from an area of higher concentration to an area of lower concentration. A concentration gradient, which is a difference in concentration of a substance across a space, is essential for this movement to occur. A hypotonic or hypertonic environment relates to osmosis in the context of cells and water - movement, not the general concept of diffusion. Dynamic equilibrium is the end - state of diffusion, not a requirement for it to start.

Answer:

A. A concentration gradient must exist.