Now a days, the farmers use which of the following instruments to separate seeds from the cob ?

Correct option is B

The correct answer is (b).
Explanation
A thresher is a modern agricultural machine used to separate grains or seeds from stalks and cobs efficiently. It saves time and labour compared to traditional manual methods.
Additional Information
• Option {a} is incorrect because rotavator is used for loosening and preparing soil. • Option {c} is incorrect because a cultivator is used for ploughing and tilling the soil. • Option {d} is incorrect because disk flask is not an agricultural implement.