low pH level. low sand content. high organic matter level. high parent rock material level.
I gave my students this multiple choice question: Topsoil is considered to be most fertile when it has a

Only one answer is correct among these 4 choices:
- low pH level.
- low sand content.
- high organic matter level.
- high parent rock material level.

Could you tell me which one is correct?

high organic matter level.