The correct answer is C. both (a) and (b).
The south Bassein and Tapti fields in the western offshore are the main producers of free gas in India. The gas fields in Tripura and Andhra Pradesh (KG Basin) are also major producers of free gas.
Free gas is a type of natural gas that is not associated with oil. It is found in gas fields that are separate from oil fields. Free gas is typically lighter than oil and has a higher energy content. It is often used to generate electricity or to power vehicles.
The south Bassein and Tapti fields are located in the Arabian Sea off the coast of Gujarat. These fields are among the largest gas fields in India. They produce about 10 billion cubic feet of gas per day.
The gas fields in Tripura and Andhra Pradesh (KG Basin) are located in the northeastern and eastern parts of India. These fields are also among the largest gas fields in India. They produce about 8 billion cubic feet of gas per day.
In conclusion, the main producers of free gas in India are the south Bassein and Tapti fields in the western offshore and the gas fields in Tripura and Andhra Pradesh (KG Basin).