The correct answer is A) Put the rudder over to the opposite side, the same number of degrees it is now. This is the correct answer because "shifting the rudder" refers to moving the rudder to the opposite side by the same amount. For example, if the rudder is currently 20 degrees to starboard, "shifting the rudder" would mean moving it 20 degrees to port. This helps the helmsman maintain control of the ship's heading and direction. The other options are incorrect because B) refers to switching steering methods, C) means putting the rudder amidships, and D) is about stopping the ship's swing, which is not what "shifting the rudder" means.