The correct answer is B) Tail shaft. In a propulsion shafting arrangement where no strut or strut bearing is required, the section of the shafting that the propeller is directly attached to is called the tail shaft. This is because the tail shaft is the rearmost portion of the propulsion shafting that extends through the stern of the vessel and connects to the propeller. The other options are incorrect because: A) Line shaft refers to the entire length of the propulsion shafting, C) Thrust shaft specifically refers to the section of the shafting that receives the thrust from the propeller, and D) Head shaft is not a commonly used term for this part of the propulsion system.