Option b is the correct answer. Option 1 is correct - Archaeologists have discovered thousands of seals, usually made of steatite, and occasionally of other materials like agate, chert, copper, faience, and terracotta. These seals were engraved with beautiful figures of animals and were used for commercial purposes, possibly as trade and identification markers. Option 2 is correct - The bricks, whether sun-dried or baked, followed a standardized ratio where the length and breadth were four times and twice the height, respectively. This uniformity in brick size demonstrates a high level of planning and organization in the construction of structures within the Harappan cities. Option 3 is incorrect - Gold bangles were found in many ancient civilizations like Harappan Civilization, Egyptian Civilization, Chinese Civilization, etc so it is not a distinctive feature of the Harappan Civilization. Option 4 is incorrect - Silver spittoons are small, cupshaped vessels that were used to spit into. Only a handful of silver spittoons were found in Harappan Civilization and they are all relatively small and simple in design. They were more likely to be found in other cultures, such as the ancient Greeks or Romans.