Metal W reacts fairly vigorously  with dilute sulphuric acid, burns easily and reacts very slowly with cold water . The MOST likely identity of W is Asodium Bcopper Ciron Dmagnesium

Based on the given information, we can determine the identity of metal W by considering its reactions with different substances.

First, it is mentioned that metal W reacts fairly vigorously with dilute sulphuric acid. This indicates that metal W is an active metal that can displace hydrogen from sulphuric acid, suggesting it is likely to be sodium or magnesium.

Next, it is stated that metal W burns easily. This characteristic is commonly associated with magnesium, as it readily reacts with oxygen to form a bright white flame. Copper and iron do not exhibit this behavior.

Lastly, metal W reacts very slowly with cold water. This observation further supports the possibility of metal W being magnesium, as it reacts slowly with water at room temperature. Sodium, on the other hand, reacts more vigorously with water, producing hydrogen gas and a strong alkaline solution.

Considering all the given information, the most likely identity of metal W is D) magnesium.