The 25 ml of a 0.15 M solution of lead nitrate, Pb(NO₃)2 reacts with all of the aluminium sulphate, Al₂(SO₄)3, present in 20 ml of a solution. What is the molar concentration of the Al₂(SO₄)3?
a) 0.30 M
b) 0.45 M
c) 0.60 M
d) 0.75 M