The correct option is D: Qualitative. Qualitative methods help to classify data collected on the basis of qualities or qualitative properties that cannot be measured using numbers.
EXPLANATION:
The manner in which corn grows in different soils can be measured in a qualitative manner like the length of the corn crop, the quality of the corn as well as the thickness of the corn plants.
This data cannot be measured in a numerical manner and so qualitative techniques are used to classify this data.
