Q37. For a sparingly soluble salt $\mathrm { AB } _ { 2 }$, the equilibrium concentrations of $\mathrm { A } ^ { 2 + }$ ions and $B ^ { - }$ions are $1.2 \times 10 ^ { - 4 } \mathrm { M }$ and $0.24 \times 10 ^ { - 3 } \mathrm { M }$, respectively. The solubility product of $\mathrm { AB } _ { 2 }$ is :\\
(1) $6.91 \times 10 ^ { - 12 }$\\
(2) $0.276 \times 10 ^ { - 12 }$\\
(3) $27.65 \times 10 ^ { - 12 }$\\
(4) $0.069 \times 10 ^ { - 12 }$