Final answer:
The boat is propelled through water by two forces.
Step-by-step explanation:
Boat propulsion refers to the mechanisms or systems used to move a boat through the water. There are various methods of boat propulsion, each with its advantages, disadvantages, and suitability for different types of vessels.
The correct answer is c) Two forces. When a boat is propelled through water, two forces are involved. One force is provided by the engine, which generates a driving force that moves the boat forward. The other force is provided by the water reacting to the oars or propeller of the boat, which creates a reactive force that pushes the boat in the opposite direction.