8.The disorder of calcium and phosphorus metabolism often appears in chronic renal failure ( )

A、Serum phosphorus ↑, serum calcium ↑;
B、Serum phosphorus ↑, serum calcium ↓;
C、Serum phosphorus ↓, serum calcium ↑;
D、Serum phosphorus ↓, serum calcium ↓;
E、Serum phosphorus is normal, serum calcium is normal