The correct answer is: a) Rajaraja Chola I and Rajendra Chola I.
Rajaraja Chola I (985-1014 CE) and his son Rajendra Chola I (1014-1044 CE) were the greatest rulers of the Chola dynasty. They expanded the Chola empire to its greatest extent, conquering much of South India, Sri Lanka, Southeast Asia, and the Maldives. They were also patrons of the arts and literature, and their reign was a golden age for the Chola kingdom.
Karikala Chola (1st century CE) was a powerful ruler who united the Chola kingdom and expanded its territory. He is also credited with building the Grand Anicut, a dam on the Cauvery River that is still in use today.
Aditya Chola I (871-907 CE) was the founder of the Chola dynasty’s second empire. He was a successful military commander who conquered much of South India. He is also credited with building the Brihadeeswarar Temple in Thanjavur, one of the largest Hindu temples in the world.
Parantaka Chola I (907-955 CE) was the son of Aditya Chola I and the father of Rajaraja Chola I. He was a successful military commander who conquered much of South India and Sri Lanka. He is also credited with building the Gangaikondacholapuram Temple, one of the largest Hindu temples in the world.
In conclusion, the Chola dynasty reached its zenith under the rule of Rajaraja Chola I and Rajendra Chola I. They were powerful rulers who expanded the Chola empire to its greatest extent and were patrons of the arts and literature.