Fick's Law of Diffusion Steps:

• Rate of diffusion = (surface area × concentration difference) / membrane thickness.
• Increase rate by maximizing surface area and concentration difference.
• Increase rate by minimizing membrane thickness.
• Compare options: A maximizes two factors (high area, high difference) despite high thickness; others have fewer favorable factors.

Why A is correct:

• High surface area and high concentration difference multiply to boost numerator in Fick's law, outweighing the high thickness denominator for fastest overall rate.

Why the others are wrong:

• B: Low concentration difference sharply reduces the rate despite high area.
• C: Low surface area limits the rate even with high difference and low thickness.
• D: All factors (low area, low difference, high thickness) minimize the rate.

Final answer: A