The correct answer is Option 3- Steatite

The most Harappan seals were made of steatite. Steatite is a soft stone that is easily carved. It is also a good insulator, which is important for seals that are used to imprint impressions in clay.

Steatite seals were found at all major Harappan sites. They are usually small, about 2 to 3 centimeters in diameter. They are often square or rectangular in shape, but they can also be circular or oval.

The seals were carved with a variety of images, including animals, plants, humans, and geometric shapes. Some of the seals also have inscriptions, which are thought to be Indus script.

The seals were used for a variety of purposes. They may have been used as tokens of ownership, as amulets, or as seals for documents. They may also have been used in trade, as a way to identify merchants and their goods.