The correct answer is c) Malappuram.
Malappuram district has the highest population density in Kerala, with 1,029 persons per square kilometer. This is followed by Ernakulam district with 967 persons per square kilometer, Thiruvananthapuram district with 856 persons per square kilometer, and Kozhikode district with 833 persons per square kilometer.
The high population density in Malappuram district is due to a number of factors, including its fertile land, its location on the Malabar coast, and its proximity to the state capital, Thiruvananthapuram. The district is also home to a number of educational institutions and industries, which have attracted people from other parts of the state and the country.
The high population density in Malappuram district has led to a number of challenges, including the shortage of housing, water, and other basic amenities. The district also faces the problem of environmental degradation, due to the rapid pace of urbanization.
The government of Kerala has taken a number of measures to address the challenges posed by the high population density in Malappuram district. These measures include the construction of new housing complexes, the provision of water and sanitation facilities, and the development of new infrastructure. The government is also working to promote sustainable development in the district.