The correct answer is D) rudder palms. The rudder palms are the horizontal flat surfaces where the upper stock joins the rudder. They provide a connection point between the rudder and the stock, allowing the rudder to pivot and steer the vessel. The other answer choices are incorrect: A) shoes of the rudder refer to the fittings that attach the rudder to the vessel's stern, B) rudder keys are used to secure the rudder stock in place, and C) lifting flanges are not associated with the rudder connection.