Calcium oxalate (CaC2O4) has a Ksp value of 2.3 × 10−9 at 25°C. Calculate the molar solubility of Ca₂⁺ and C₂O₄²− in one liter of aqueous solution. Which is the correct set-up?
a) Ksp = [x] × [4x]⁴
b) Ksp = [x] × [x]
c) [CaC2O4] = [x] × [x]
d) Ksp = [2x] × [x]⁴