What is the meaning of the term "qilachas" in the context of medieval India?

Fortresses

The correct answer is Option 1 - Fortresses

Most zamindars had fortresses (qilachas) as well as an armed contingent comprising units of cavalry, artillery and infantry.

Zamindars were landed proprietors who also enjoyed certain social and economic privileges by virtue of their superior status in rural society. Caste was one factor that accounted for the elevated status of zamindars; another factor was that they performed certain services (khidmat) for the state. The zamindars held extensive personal lands termed milkiyat, meaning property. Milkiyat lands were cultivated for the private use of zamindars, often with the help of hired or servile labour. The zamindars could sell, bequeath or mortgage these lands at will. Zamindars also derived their power from the fact that they could often collect revenue on behalf of the state, a service for which they were compensated financially. Control over military resources was another source of power. Most zamindars had fortresses (qilachas) as well as an armed contingent comprising units of cavalry, artillery and infantry.