Economic                 Geographic               Social
                   Aspect                      Aspect                      Aspect

D)                     3                                2                               1

1. the farms were rectangular in shape and perpendicular to the river;
    Not Correct !        (Shapes are not "social")

2. the people put their efforts into developing agriculture;
    Correct !        (Agriculture is an economic activity)

3. the corvées (free labour) promoted the exchange of services.
    Not Correct !       (Not an economic activity)     Social activity ?