Harappan civilization, part of the Indus Valley Civilization, is known for its highly sophisticated urban planning, one of the distinguishing features being the extensive use of standardized, baked bricks. This made the buildings more durable and allowed the cities to have well-organized streets and drainage systems. The use of bricks for construction was far more advanced compared to other ancient civilizations, which commonly used wood, stone, or other materials.
The Harappans built large cities such as Harappa and Mohenjo-Daro with houses, public baths, and drainage systems made from fired bricks, which could withstand the humid climate better than unbaked bricks or wood. Therefore, the correct answer is (C) Use of Bricks.