A. Cl¯ moves down its concentration gradient through apical Cl¯ channels.
B. Na+/K+-ATPase pumps Na+ out of lumen cells.
C. Na+ diffuses out between lumen cells.
D. Cl¯ and K+ enter lumen cells via Na+ cotransport mechanism.
B, D, A, C
B, C, A, D
B, A, D, C
D, B, A, C