The correct option is D Dome
Kos Minars or Mile Pillars are medieval milestones that were made by the 16th-century Afghan Ruler Sher Shah Suri and later on by Mughal emperors. They are plastered solid bricks structures standing on a square platform. Each minar has a dome shaped tip emerging from a tapering octagonal base. They were erected to serve as markers of distance along royal routes from Agra to Ajmer, Agra to Lahore, and from Agra to Mandu in the south. They were an important part of communication and travel in a large empire.