The Pallava capital city was:

Kanchipuram
Madurai
Mamallapuram
Thanjavur

The correct answer is: a) Kanchipuram.

Kanchipuram was the capital of the Pallava dynasty from the 3rd to the 9th centuries CE. It is located in the modern-day state of Tamil Nadu, India. The city is known for its many temples, which are some of the finest examples of Pallava architecture.

Madurai was the capital of the Pandya dynasty from the 6th to the 13th centuries CE. It is located in the modern-day state of Tamil Nadu, India. The city is known for its many temples, which are some of the finest examples of Dravidian architecture.

Mamallapuram was a port city and the second capital of the Pallava dynasty from the 7th to the 9th centuries CE. It is located in the modern-day state of Tamil Nadu, India. The city is known for its many rock-cut temples and sculptures, which are some of the finest examples of Pallava art.

Thanjavur was the capital of the Chola dynasty from the 9th to the 13th centuries CE. It is located in the modern-day state of Tamil Nadu, India. The city is known for its many temples, which are some of the finest examples of Chola architecture.