Exchanges were regulated by a precise system of weights, usually made of a stone called chert and generally cubical with no markings. The lower denominations of weights were binary (1, 2, 4, 8, 16, 32, etc. up to 12,800), while the higher denominations followed the decimal system. The smaller weights were probably used for weighing jewellery and beads. Metal scale-pans have also been found.

So, the correct option is [3].