Use the map to answer the question. a map shows the locations of mill towns east of the mississippi river. there are two mill towns marked in massachusetts, and one marked in each of the following states: new hampshire, connecticut, new jersey, pennsylvania, virginia, indiana, illinois, georgia, and mississippi. based on the information on the map, what can you infer about industry in the united states? a. manufacturing was a key part of the economy in the northeast. b. agriculture was the major industry in the south. c. mills in the northeast had to be close to ports to make it easier to transport factory-made goods. d. population levels in the midwest made it difficult to support the amount of labor required to industrialize.