The soil in a backyard garden contains a large amount of clay. What could be done to improve the quality of the soil for gardening?

Select one:
a. The soil could be dug up and tilled.***
b. Acid could be added to the soil.
c. More clay could be added to the soil.
d. The soil could be irrigated.
I think its A but what if it makes it easier to erode the soil?

The question is silly, and answer A is the best answer. One imporves clay soil by adding organic material to it. Tilling it starts the process of removing imperious boundries.