When solid PbCO₃ is heated, it decomposes to form solid PbO and CO₂ gas. Express the balanced chemical equation for this reaction with integer coefficients for all species in the reaction from left to right, separated by commas.
a) 1, 1, 1
b) 1, 1, 2
c) 1, 2, 1
d) 2, 1, 1
