The correct answer is b) Palakkad.
Palakkad is a district in Kerala, India. It is the second most populous district in Kerala after Ernakulam. The district has a population of 3,389,213 as of 2011. The district is known for its cattle population. As of 2011, the district had a cattle population of 2,411,626. This is the highest cattle population in any district in Kerala.
The other options are incorrect. Thiruvananthapuram is the capital of Kerala and has a population of 1,014,855. Malappuram is the third most populous district in Kerala and has a population of 3,193,795. Idukki is the fourth most populous district in Kerala and has a population of 2,327,911.
The cattle population in Kerala is important for the state’s economy. The state is a major producer of milk and milk products. The cattle population also provides employment to a large number of people in the state.