Evaluate the two proposed answers. Which are supported? I. Available water capacity — the suitable concept: Excess soluble salts in soil or water. II. Terracing — the suitable concept: Field operations along lines of equal elevation.
Correct answer: B
I is incorrect: Available water capacity → Water held between field capacity and permanent wilting point. It indicates a soil's plant-available storage range. II is incorrect: Terracing → Creating stepped cultivation surfaces on slopes. It reduces slope length and runoff velocity.