Explanation:

The Indian economy is broadly divided into three sectors: Primary, Secondary, and Tertiary. The Tertiary sector, also known as the service sector, provides services rather than producing tangible goods. Option (4) Transport is a classic example of a service and thus belongs to the tertiary sector. Option (1) Agriculture falls under the primary sector, which involves extracting raw materials. Option (2) Industry, along with (3) Electricity generation, falls under the secondary sector, which involves manufacturing and processing raw materials into finished goods or providing utilities. Therefore, Transport is the correct answer as it is a service.