Final answer:
Oars must be perpendicular to the boat's movement to maximize propulsion by efficiently converting the rower's energy into forward motion and avoiding unnecessary drag. Therefore correct answer is c.
Step-by-step explanation:
In rowing, it is important for the oars to be positioned perpendicular to the direction of the boat's movement in order to maximize propulsion. The force that moves a boat forward when someone rows is caused by an interaction between the oars and the water the boat is traveling in. When the oars are perpendicular to the boat, they can push against the water most effectively, thus creating the greatest amount of force to propel the boat forward.
Conversely, if the oars were not perpendicular, it would result in a less efficient stroke, decreasing the force applied to move the boat and making it harder to steer accurately.
Furthermore, the perpendicular position helps avoid unwanted drag or resistance that would slow the boat down. This is crucial as it ensures that the energy exerted by the rower is converted into forward movement as efficiently as possible. Resistance caused by water interacting with the boat's hull and oars is a key factor in the dynamics of rowing, but the resistance experienced by the oars in the water is what generates the propulsive force.