Answer:
i believe its A but im not sure
its the only one that makes any sense
plz mark brainliest
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Explanation:
Answer : Option 4) 
Explanation :
is the only sample of matter which can be classified as a solution. As the solution can be defined as a liquid mixture which contains a minor component (the solute) that is uniformly distributed within the major component (the solvent).
In this case, the solute is
which is dissolved in water which acts as an solvent. Also, it has a subscript which is aq. which means aqueous, is often given to the solution in which the solvent is water.
Therefore,
is the correct answer.
It is an alkaline earth metal.