29. A protein mixture contains proteins A, B, and C (Protein A: homodimer M. = 140,000, pI 8; Protein B: Mr = 113,000, pI 5; Protein C: Mr = 13,000, pI 9).
1. Sandy used SDS-PAGE to separate theses three proteins. The sequence of the protein bands shown in gel from top to bottom is A-B-C.
2. Simon dissolved the protein mixture in 20 mM phosphate buffer (pH 7) and loaded to a cation exchange column equilibrated with the same buffer. Protein B could not bind to the column.
3. Samuel dissolved the protein mixture in 20 mM phosphate bufter (pH 7) and loaded to an anion exchange column equilibrated with the same buffer. Only protein A and C could bind to the column.
4. Silvia used a gel filtration column to separate them, C will be eluted first.
5. Sophie used 2-Dimensional electrophoresis to separate them. The relative positions of these three proteins is like the image below.

(A) 1, 2, and 5 are correct.
(B) 2 and 4 are incorrect.
(C) 1, 3, and 4 are incorrect.
(D) Only 2 is correct.
(E) Only land 3 are incorrect.