Which of the following metals give hydrogen with all three reactants; water, acid, alkali.
 $ A. $ $ Fe $
 $ B. $ $ Zn $
 $ C. $ $ Mg $
 $ D. $ $ Na $

Hint: The entire above element is given is metal. Metal is hard, sonorous, lustrous, malleable (can be drawn into a thin sheet) and ductile (can be drawn into wire). Generally they are good conductors of heat and electricity. They also show colour property.

Complete step by step answer
The chemical properties of metal give hydrogen with water, acid and alkali. In the given question out of all the metal one metal doesn’t give hydrogen with all the reactant. Let us see their reaction with all the reactants.
Reaction of $ Fe $ with all the reactant,
 $ Fe + 2HCl \to FeC{l_2} + {H_2} $ (React with acid)
 $ Fe + NaOH \to $ No reaction (With alkali)
 $ 3Fe + 4{H_2}O \to F{e_3}{O_4} + 4{H_2} $ (With water as steam)
Similarly, Reaction of $ Zn $ with all the three reactants,
 $ Zn + 2HCl \to ZnC{l_2} + {H_2} $ (With acid)
 $ Zn + 2NaOH \to N{a_2}Zn{O_2} + {H_2} $ (With alkali)
\[Zn + {H_2}O \to Zn{\left( {OH} \right)_2} + {H_2}\] (With water
Reaction of $ Mg $ with all the three reactant,
 $ Mg + 2HCl \to MgC{l_2} + {H_2} $ (With acid)
 $ Mg + NaOH \to $ No Reaction
Under normal conditions, magnesium metal does not react with an aqueous solution of sodium hydroxide.
 $ Mg + 2{H_2}O \to Mg{\left( {OH} \right)_2} + {H_2} $ (With water)
And, reaction of $ Na $ with all three reactant,
 $ Na + 2HCl \to NaCl + {H_2} $ (With acid)
 $ 2Na + 2{H_2}O \to 2NaOH + {H_2} $ (With water)
 $ Na + NaOH \to $ No reaction
As sodium is also an alkali metal it does not react with base and does not give hydrogen gas.
From the above reaction it may conclude that only Zinc $ \left( {Zn} \right) $ metal will give Hydrogen $ \left( {{H_2}} \right) $ gas with all the reactant that is water, acid and alkali.
Thus, the correct option is $ B. $

Note
Among all the given metal sodium is highly reactive metal is readily react with water to produce Hydrogen gas and can cause for. So, for safety purposes Sodium is kept in kerosene which makes it less reactive and stable. Generally all the elements of the first group are more reactive.