The correct answer is: A) Karur.
Karur was the capital of the Chera kingdom from the 3rd century BCE to the 3rd century CE. It is located in the modern-day state of Tamil Nadu, India. Karur was an important center of trade and commerce, and it was also a major religious center. The city was home to many temples and monasteries, and it was a popular pilgrimage destination.
Karur was a prosperous city, and it was known for its fine textiles and jewelry. The city was also a center of learning, and it was home to many scholars and poets. Karur declined in importance after the 3rd century CE, but it remains an important historical site.
The other options are incorrect because they were not the capital of the Chera kingdom.
B) Madurai was the capital of the Pandya kingdom.
C) Kollam was the capital of the Venad kingdom.
D) Thiruvananthapuram was the capital of the Travancore kingdom.