From deoxygenated blood entering the heart to oxygenated blood leaving the heart, in which order will the blood pass through the following valves?

A. Parietal Cell: Parietal cells are responsible for secreting hydrochloric acid (HCl) and intrinsic factor, not pepsinogen. HCl activates pepsinogen into pepsin.

B. Mucous Neck Cell: Mucous neck cells secrete mucus to protect the gastric lining but do not secrete pepsinogen.

C. Chief Cell: Chief cells (also known as zymogenic cells) are specialized cells in the stomach that secrete pepsinogen, the inactive precursor of the digestive enzyme pepsin.

D. Enteroendocrine Cell: Enteroendocrine cells secrete hormones like gastrin, which regulates digestive processes, but they do not secrete pepsinogen.

A. Memory T cell: Memory T cells are important for the adaptive immune response and provide cellular immunity but are not responsible for producing antibodies.

B. Memory B Cell: Memory B cells remain in the body after an infection has been cleared and are responsible for producing specific antibodies upon re-exposure to the same pathogen.

C. Natural killer cell: Natural killer cells are part of the innate immune system and function to kill virally infected cells and tumors but do not produce antibodies or have memory capabilities.

D. Mast cell: Mast cells are involved in allergic reactions and defense against parasites but do not produce antibodies and are not part of the memory response.