Which of the following provisions for thermal expansion for shell-and-tube heat exchangers has a tube arrangement featuring a "tube-within-a-tube"?

Correct Answer: Option C — A shell-and-tube heat exchanger featuring bayonet type tubes.

Bayonet-type tubes consist of an outer tube closed at one end and an inner tube open at both ends. This tube-within-a-tube arrangement allows the heating medium to flow through the inner tube and return through the annulus, providing inherent thermal expansion capabilities essential for high-temperature fuel oil service heaters.