Right option is (a) True
Explanation: Magnesium is the lightest material in all the engineering materials. It has good ductility, better noise and vibration damping features than aluminium and also has excellent cast-ability. Alloying of magnesium metal with aluminium, manganese increases the strength of the components and also reduces the weight of the casted parts, so magnesium alloys are very important materials for applications where weight saving is a dominant objective.