The Indus Valley Civilisation is also known as —

The Indus Civilisation is also called the Harappan Civilisation because Harappa was the first major site excavated that gave its name to the archaeological culture. It was not Vedic, Mesopotamian or simply ‘Aryan’. The Harappan Civilisation fits that evidence because it matches the specific chronology, agency and function contained in the question. A comparison with the alternatives is useful: The Mesopotamian Civilisation, The Vedic Civilisation and The Aryan Civilisation are genuine historical terms or names, but each belongs to a different office, patron, text, region or sequence. The supporting source also helps separate later textbook shorthand from the more precise historical formulation. The compact memory link is therefore The Harappan Civilisation together with the factual context above, not the isolated option letter.