4. For two monoprotic acids (HA, HB) and their conjugate bases (A- , B- ), the following relations are known: HA + B- A- + HB, K ＞ 1 and pKb(A- ) ＜ 7.0. Which of the following order of K’s is correct? (A) Kb(B- ) ＞ Ka(HB) ＞ Ka(HA) ＞ Kb(A- ) (B) Kb(A- ) ＞ Kb(B- ) ＞ Ka(HA) ＞ Ka(HB) (C) Kb(B- ) ＞ Kb(A- ) ＞ Ka(HA) ＞ Ka(HB) (D) Kb(B- ) ＞ Ka(HA) ＞ Kb(A- ) ＞ Ka(HB)