Which of the following helps in maintaining soil fertility?

The correct option is C Crop rotation
$\bullet$ Crop rotation is the practice of growing a series of dissimilar crops in the agricultural land in sequenced seasons. This practice of rotation replenishes soil nutrients and increases soil fertility. It also controls the spread of pests and diseases to increase crop yield.
$\bullet$ Herbicides and pesticides are chemical substances that prevent the growth of unwanted weeds and pests respectively but are significantly harmful to humans and animals.
$\bullet$ Tissue culture is a technique used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition.