The correct option is D Weeding is only done manually.
Weeding is the process of removal of weeds (unwanted plants) in an agricultural land. It is a necessary step as the weeds start competing with the crop plants for water, nutrients, sunlight, etc. They adversely affect the growth of the crop. The best time for the removal of weeds is before they produce flower and seeds (mature). So that they do not interfere with the harvesting process. Weeding can be done manually using tools like khurpi or chemically by using weedicides.