The correct option is B The Harappans constructed planned cities, traded with other civilisations, and possessed their own writing system.
The Harappans had organised themselves into stable and efficient societies. There exists evidence of their development in various aspects of life, like language, art, architecture, education, and intellectual pursuits. They constructed planned cities, traded with other civilisations, and possessed their own writing system. These are factors that contribute to it being classified as a 'civilisation'.