Consider the following pairs of solution which will be isotonic at the same temperature. The number of pairs of solutions is/are...... A. 1 M aq. NaCl and 2 M aq. Urea B. 1 M aq. CaCl2 and 1.5 M aq. KCl C. 1.5 M aq. AlCl3 and 2 M aq. Na2SO4 D. 2.5 M aq. KCl and 1 M aq. Al2(SO4)3