In the lymphatic system, the component most closely associated with cardiovascular capillary beds is the lymphatic capillaries. These capillaries play a crucial role in fluid balance within the body. Cardiovascular capillary beds are known to lose fluids to surrounding tissues, and lymphatic capillaries are essential for reabsorbing this lost fluid and returning it to the cardiovascular system.

To understand why other options are not correct, consider the thymus and lymph nodes. The thymus is a lymphoid organ with its own blood supply, but it is not associated with all capillary beds throughout the body, making it an unsuitable choice. Similarly, while lymph nodes are strategically located and have their own blood supply, they do not connect with every capillary bed, which disqualifies them as the correct answer.

On the other hand, lymphatic trunks, which are larger vessels in the lymphatic system, do not have the same close association with capillary beds as lymphatic capillaries do. Therefore, the correct answer to the question is lymphatic capillaries, as they are integral to the process of fluid recovery from the tissues, ensuring that the cardiovascular system maintains proper fluid levels.