Identify the economic activities in the following case and classify them into Primary, Secondary and Tertiary industies

Identify the economic activities in the following case and classify them into Primary, Secondary and Tertiary industies.
(a) Mohan, a farmer producing wheat
(b) Raj, the owner of a cotton textile firm.
© Ramesh, is working as a peon in an oil refinaty.
(d) Krishna, is running her advertisement agency.

(a) Farmer—Business—Primary industry.
(b) Owner of a cotton textile firm—Business secondary industry.
© Peon—Employment—Secondary industry.
(d) Advertisement agency—Profession—Tertiary industry