The correct answer is: A. The Abhira
Mahismati was the earliest seat of power of the Abhira. The Abhira were an ancient Indian tribe that ruled over a large area of central India from the 3rd century BCE to the 6th century CE. Their capital was Mahismati, which is located on the banks of the Narmada River in the present-day state of Madhya Pradesh.
The Abhira were a powerful and influential tribe. They were known for their military prowess and their skill in horsemanship. They were also known for their love of music and dance.
The Abhira were eventually overthrown by the Gupta Empire in the 6th century CE. However, their legacy continued to live on in the region. The city of Mahismati was later renamed Mandu, and it became an important center of Hindu and Jain culture.
The other options are incorrect. The Kalachuris were a dynasty that ruled over parts of central India from the 6th to the 13th centuries CE. The Vachanas were a group of religious reformers who lived in the 12th and 13th centuries CE. None of these groups ruled over Mahismati in the 3rd century BCE.