The correct answer is C) crossover. A crossover system refers to the network of valves and cargo lines that connect different sections or groups of cargo tanks on a tank vessel. This allows the transfer of cargo between different tank sections, enabling efficient loading, unloading, and management of the vessel's cargo. The crossover system is a critical component of the tank vessel's bottom piping network and is essential for the safe and effective transportation of liquid cargo. The other options are incorrect because: A) A come-along is a type of mechanical device used for lifting or pulling, not a component of the cargo tank system. B) A runaround is not a term commonly used to describe the cargo tank piping network. D) A manifold is a component that distributes or collects fluid flow, but it does not specifically refer to the crossover system between cargo tank sections.