A prehistoric site in Kerala known for urn burials is:

Porkalam
Wayanad
Kannur
Kasaragod

The correct answer is A) Porkalam.

Porkalam is a prehistoric site in Kerala known for urn burials. It is located in the Palakkad district of Kerala, India. The site was discovered in 1968 by a team of archaeologists from the Archaeological Survey of India. The site has yielded a large number of urn burials, as well as other artifacts such as pottery, stone tools, and beads. The urn burials date back to the Iron Age, and are believed to be the remains of a people who practiced a form of ancestor worship.

The site of Porkalam is significant because it provides evidence of the early history of Kerala. The urn burials and other artifacts found at the site provide insights into the culture and beliefs of the people who lived in Kerala during the Iron Age. The site is also important because it is one of the few prehistoric sites in Kerala that has been excavated and studied by archaeologists.

The other options are incorrect because they are not prehistoric sites in Kerala known for urn burials. Wayanad is a district in Kerala, India. Kannur is a district in Kerala, India. Kasaragod is a district in Kerala, India.