(i) c

Sickle is used for manual harvesting. Harvesting is the process of cutting and gathering matured or ripened crops.

(ii) a

Hoe is an agricultural implement which is a long rod of wood or iron with a broad, bent and strong iron plate at its one end which is used to remove weeds. It is also used for loosening soil.

(iii) b

Seed drill is a mechanical method of sowing seeds using a tractor. It is a long iron tube having a funnel at the top where seeds are put and seeds are gradually released into soil furrows.

(iv) d

Sprinkler is a modern method of irrigation where water is sprinkled from revolving nozzles connected to water pipelines.