Which of the following artefacts were used by the Harappans for long distance communication?

Seal and Sealings

Features of Harappan seals:

The seals were the most distinctive object of the Harappan civilization & made of a stone called steatite.
Seals often contained animal motifs and signs from a script that remains un-deciphered.
The seals were generally square or rectangular in shape.
Seals and sealings played a crucial role in enabling long-distance communication.
A bag's mouth was tied with rope to ensure the security of goods during transportation, and wet clay was applied to the knot. One or more seals were pressed onto the clay, leaving distinct impressions.
Upon the bag's arrival, the intact sealing indicated that it had not been tampered with.
It also served to convey the sender's identity, providing information about the origin of the goods.