When Blood Ca²⁺ Levels Fall Below Normal,in What Ways Do

When blood Ca²⁺ levels fall below normal,in what ways do the kidneys help restore them toward normal?

A) By increasing 1,25-dihydroxyvitamin D₃ formation,decreasing tubular phosphate reabsorption,and increasing tubular Ca²⁺ reabsorption
B) By increasing 1,25-dihydroxyvitamin D₃ formation,increasing tubular phosphate reabsorption,and increasing tubular Ca²⁺ reabsorption
C) By decreasing 1,25-dihydroxyvitamin D₃ formation,increasing tubular phosphate reabsorption,and increasing tubular Ca²⁺ reabsorption
D) Increasing 1,25-dihydroxyvitamin D₃ formation and increasing secretion of parathyroid hormone
E) By increasing renal secretion of parathyroid hormone and increasing bone resorption