The correct answer to this open question is the following.
You forgot to include the reference or the graphic showing the economic activities. However, doing some research, we can say the following.
A similarity between the economic activities of Region "A" and Region "C" is that both regions depended on trade to generate an income. The New England Colonies did not have success in farming the fields because the soil was rocky. That is why they focused on fishing activities and on building ships to hunt whales.
In the case of the Southern colonies, they also depended on trade, but what they traded was their cash crop production. These southern colonies grew tobacco, indigo, and rice, and the crops were traded with other colonies but also were exported to Europe.