已知K_sp(AB₂)=4.2×10^-8,K_sp(AC)=3.0×10^-15，在AB₂、AC均为饱和的混合液中,测得c(B^-)=1.6×10^-3 mol·L^-1,则溶液中c(C^2-)为        （   ）

A.1.8×10^-13 mol·L^-1             B.7.3×10^-13 mol·L^-1

C.2.3 mol·L^-1                   D.3.7 mol·L^-1

Directions:This section consists of three groups of pairs listed in two columns, A and B. You are to match the one marked 1), 2), 3) ,4) or 5) in Column A with the one marked a, b, c, d or e in Column B. One point is given to each pair you match.
1) ______ Jean Piaget
2) ______ M. A. K. Halliday
3) ______ J. Schumann
4) ______ Joseph H. Greenberg
5) ______ B.F. Skinner
a) field, tenor and mode concept
b) neo-behaviourism
c) cognitive psychology
d) the hypothesis of linguistic universals
e) the acculturation theory