A metal M forms the sulphate M₂(SO₄)₃. A 0.596g sample of the sulphate reacts with excess BaCl₂ to give 1.220g BaSO₄. What is the atomic weight of M? (Atomic weights: S=32,Ba=137.3)
A. 26.9
B. 69.7
C. 55.8
D. 23