3. The formula of Plaster of Paris is \( CaSO _{4} .1 / 2 H _{2} O \), it is to be noted that half water molecule is shown to be attached as water of crystallisation. This indicates that A. Only half water molecule is present in Calcium Sulphate crystal B. Two formula units of Calcium Sulphate share one molecule of water. C. Two formula units of calcium Sulphate share two molecules of water D. Two formula units of Calcium Sulphate share one and a half molecules of water.