A student adds 0.750 g of solid PbCO₃ (molar mass 267.2 g mol⁻¹) to 200.0 mL of pure water at 25 °C and allows the mixture to reach equilibrium. The solubility-product constant for PbCO₃ at this temperature is 7.4×10⁻¹⁴. Which of the following is closest to the mass of PbCO₃ that remains undissolved?
a) 0.000015g
b) 0.749g
c) 0.150g
d) 0.750g