The correct options are
B The volume of trade with Mesopotamia would have been far lesser.
C Street corners would not have been curved.
D The main roads of their cities would have been much smaller.
The absence of wheeled transport could have reduced the amount of goods being exchanged between the two civilisations primarily because of the convenience lent by its use. The Harappans paid close attention to their town planning wherein they created large main roads possibly for the smooth passage of their wheeled transport. Additionally, despite creating roads and streets that were interconnected at perfect right angles, they also ensured that they were slighly curved so as to allow heavy carts to turn with ease—something that might not have been the case in the absence of wheeled transport.