The plumber used a tube to open up the curved pipe. What type of tube did the plumber most likely use?

A solid tube lacks the necessary flexibility to navigate through curved pipes. Solid tubes are rigid and inflexible, making them unsuitable for tasks requiring maneuverability around bends. Such properties limit their use to applications involving straight pathways or structural support.

Rigid tubes, by definition, are not able to bend and conform to the shape of curved pipes. While they may be used in plumbing for certain applications, they are not ideal for accessing or clearing blockages in pipes with bends. The lack of flexibility would prevent the tube from traversing curved sections effectively.

Perforated tubes contain holes or openings along their length, which are typically used in applications requiring drainage or aeration, rather than navigating curved paths. While they can be flexible, the presence of perforations is not relevant to the task of clearing obstructions in a curved pipe.