Which of the following statements regarding the metabolism of bilirubin is true?

Bilirubin is primarily produced from the catabolism of heme, specifically during the breakdown of hemoglobin in red blood cells (RBCs). When RBCs reach the end of their lifespan, they are engulfed by macrophages, particularly in the spleen and liver. During this process, the heme portion of hemoglobin is converted into bilirubin, which is then released into the bloodstream. This pathway highlights the essential relationship between bilirubin production and the destruction of RBCs, making the statement that it is produced from the destruction of RBCs true.

In contrast, the other options misrepresent aspects of bilirubin metabolism or relate to different biochemical processes. For instance, hydrolysis of urobilinogen pertains to bilirubin elimination but does not contribute to bilirubin formation. While biliverdin is a metabolite of heme degradation, bilirubin is formed from biliverdin, not the other way around. Lastly, while bilirubin production is connected to porphyrin metabolism, it is not accurate to classify bilirubin as a direct by-product of porphyrin production. These contexts clarify why the selected statement accurately describes bilirubin metabolism.