Certain pipe organs act like columns closed at one end. If the fundamental frequency resonates in that column, which pattern best represents this case of resonance? Question 15 options: a) A pipe with a closed end. Inside the wave starts at a node half way up the pipe and becomes an anti-node at the open end. b) A pipe closed at the bottom. The wave connects to the closed end at the anti-node and then goes to a node in the middle before creating a second anti-node at the opening of the pipe. c) A pipe with a closed bottom. Inside the wave connects to the closed end at a node. The wave then becomes an anti-node followed by a node and finishing with a second anti-node as it moved towards the open end. d) A pipe closed at the bottom. Inside the node of the wave conects with the closed end and one anti-node stretches up the tube to the open end. e) None of these diagrams are correct