The port city of Kollam (Quilon) was an important trading center during the:

Chera Dynasty
Medieval Period
Colonial Era
All of the above

The correct answer is D) All of the above.

The port city of Kollam (Quilon) was an important trading center during the Chera Dynasty, the Medieval Period, and the Colonial Era.

The Chera Dynasty was a major power in southern India from the 3rd century BCE to the 12th century CE. Kollam was one of the most important ports of the Chera kingdom, and it was a major center for trade with the Roman Empire.

The Medieval Period in India is generally considered to be the period from the 6th to the 16th centuries CE. During this time, Kollam continued to be an important trading center, and it was also a major center for the production of spices.

The Colonial Era in India began in the 16th century with the arrival of the Portuguese. Kollam was one of the first ports in India to be occupied by the Portuguese, and it remained under Portuguese control for over 100 years.

After the Portuguese, the Dutch and the British also occupied Kollam. The city remained an important trading center under all three colonial powers.

Today, Kollam is a major port city in Kerala, India. It is a major center for trade, industry, and education.