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