What can a drop of liquid mercury be described as

What can a drop of liquid mercury be described as?

a) a pure substance and a compound

b) an impure substance that is reactive

c) an impure substance that is unreactive

d) a pure substance and an element

Explanation:

Pure substances are those where there is only one type of atom or molecule present, and have a constant composition (has the same composition of elements by mass).

Generally, in a single drop of mercury there are no impurities, therefore  the sample will have only one type of atom present, as mercury is an element (it only contains one type of atom), making it a pure substance and an element.