The primary mode of public transportation within Kerala is:

Buses
Trains
Taxis
Auto rickshaws Answer: a

The primary mode of public transportation within Kerala is buses. The Kerala State Road Transport Corporation (KSRTC) is the largest public transport corporation in Kerala, operating a fleet of over 15,000 buses. The KSRTC operates buses to all parts of the state, including rural areas. The KSRTC also operates a number of express buses that connect major cities in Kerala.

Trains are also a popular mode of public transportation in Kerala. The Indian Railways operates a number of trains to Kerala, including the Thiruvananthapuram-Ernakulam Intercity Express, the Mangalore-Palakkad Express, and the Chennai-Kochuveli Express.

Taxis are available in major cities in Kerala. Taxis are metered and fares are regulated by the government. Auto rickshaws are also available in major cities in Kerala. Auto rickshaws are not metered and fares are negotiated with the driver.

The correct answer is: a) Buses.