Economic                 Geographic               Social
                   Aspect                      Aspect                      Aspect

B)                     2                                1                               3

1. the farms were rectangular in shape and perpendicular to the river;
    Correct !      (Shape is geographic)

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.
    Correct !     (Exchanging services is social)