Final answer:
Local conservation commissions are usually responsible for approving or denying riverfront property developments under the Massachusetts Rivers Protection Act.
Step-by-step explanation:
Under the Massachusetts Rivers Protection Act, the responsibility to approve or deny the proposed building of a property along a riverfront generally falls to B the local conservation commission.
This is the body typically tasked with overseeing and enforcing state and local environmental regulations, including those related to waterways and riverfront areas.
Although the Massachusetts Department of Environmental Protection may provide overarching policy guidance and the Environmental Protection Agency (EPA) sets broader water quality standards, it is the local commission that often has the direct authority to approve such developments.