Cyperinus rotundus and Parthenium are types of:

The correct answer is Option (3) → Weeds

Weeds are unwanted plants that grow among crops and compete with them for water, nutrients, sunlight and space, lowering the yield. Both plants named are common weeds in India:

• Cyperinus rotundus (correctly spelt Cyperus rotundus) — nut grass (motha), one of the worst weeds of crop fields, which spreads by underground tubers

• Parthenium — carrot grass or congress grass (gajar ghas), which spreads fast on waste land and fields and can cause skin allergy and asthma