Concept:The salt content of blood refers to the total dissolved inorganic salts, mainly in the plasma.Explanation:Blood plasma contains a small but essential amount of dissolved salts.These salts include sodium chloride, bicarbonates, and other electrolytes.The normal total salt concentration in blood plasma is approximately 0.85% to 0.9%.This is a standard physiological value often tested in exams.Comparing with the options, only option D lies within this range.Answer:D. 0.85% to 0.9%