Endogamy refers to the practice of marrying within one's own community, caste or social group. Among the given options, the Satavahanas were the rulers who followed endogamy.

Explanation:

Satavahanas:
- The Satavahanas were a dynasty that ruled over parts of present-day India from the 1st century BCE to the 3rd century CE.
- They were known for their strong administrative skills, patronage of art and literature, and promotion of Buddhism.
- The Satavahanas followed endogamy and were known to marry within their own clan or gotra.
- This practice was aimed at maintaining the purity of the royal bloodline and avoiding any dilution of power.

Pandavas:
- The Pandavas were a legendary dynasty mentioned in the Hindu epic Mahabharata.
- They are believed to have lived in the ancient Indian city of Hastinapura.
- However, it is not clear whether they followed endogamy or not, as the Mahabharata does not provide detailed information about their marriage practices.

Mauryas:
- The Mauryas were a dynasty that ruled over India from the 4th century BCE to the 2nd century BCE.
- They were known for their strong military and administrative skills, and their promotion of Buddhism.
- However, there is no evidence to suggest that they followed endogamy.

Therefore, the correct answer is option A, the Satavahanas were the rulers who followed endogamy.