Option a is the correct answer. The Satavahana dynasty was the most powerful dynasty in Southern India after the Maurya dynasty. They ruled over the Deccan region, comprising present-day Andhra Pradesh, Telangana, and Maharashtra, and at different times, their rule extended to parts of modern Gujarat, Madhya Pradesh, and Karnataka. The dynasty began around the late second century BCE and lasted until the early third century CE. The Satavahanas established peace in the Deccan region and resisted foreign invasions, notably from the Saka (Western Satraps). Their rule reached its peak under rulers like Gautamiputra Satakarni and Vasisthiputra Pulamavi. They also played a significant role in trade and cultural exchanges between the northern and southern parts of India.