Which blood type can be safely transfused to any patient regardless of their ABO group?

A. The adrenal gland's hormones are primarily steroid-based:Many adrenal cortex hormones (glucocorticoids, mineralocorticoids, and androgens) are steroid hormones derived from cholesterol, distinguishing them chemically from many pituitary peptides.
B. The adrenal gland's hormone release is regulated by thyroid hormones:While thyroid hormones affect metabolism broadly, they are not the main regulators of adrenal hormone release; ACTH and the HPA axis primarily regulate adrenal cortisol production.
C. The pituitary gland's hormone release is directly controlled by the hypothalamus:The hypothalamus controls anterior pituitary hormone secretion via releasing and inhibiting hormones delivered through the hypophyseal portal system.
D. The pituitary gland produces hormones in response to blood glucose levels:Some pituitary functions can be influenced indirectly by metabolic state, but direct regulation of pituitary hormone release by blood glucose is not a primary mechanism.

A. Defending against infections:Red blood cells do not have immune functions; defense against infection is primarily the role of white blood cells.
B. Clotting blood:Clotting is mainly mediated by platelets and clotting factors in plasma, not by red blood cells.
C. Transporting oxygen:Red blood cells contain hemoglobin, which binds oxygen in the lungs and carries it to tissues — their primary function.
D. Carrying nutrients:Nutrient transport is primarily performed by plasma (dissolved nutrients) and the digestive/transport systems, not red blood cells.