The most famous of the early Chola kings mentioned in Sangam literature is:

The correct answer is: a) Karikala Chola.

Karikala Chola was the most famous of the early Chola kings mentioned in Sangam literature. He was the son of Vijayalaya Chola, who founded the Chola dynasty in the 9th century CE. Karikala Chola is credited with expanding the Chola kingdom and defeating the Pallavas, who were the dominant power in South India at the time. He is also known for his military reforms and for building a number of temples and irrigation canals.

The other options are incorrect because:

• Rajendra Chola was a later Chola king who ruled in the 11th century CE. He was the son of Chola emperor Rajaraja I and is considered to be one of the greatest military commanders in Indian history.
• Aditya Chola was a Chola king who ruled in the 10th century CE. He was the son of Parantaka Chola I and is credited with expanding the Chola kingdom into the Deccan.
• Parantaka Chola I was a Chola king who ruled in the 10th century CE. He was the son of Aditya Chola and is credited with defeating the Pandyas and the Cheras, who were the two other major powers in South India at the time.