Hello
To solve this question, we should understand that an element is is the base form in which a particule exit. However, it can either be in a molecule, atom or in a compound. Elements are pure substance which form up the molecule, atom or compounds. An element can said to be an identity of a substance. Elements are generally classified using the periodic table into metals, non-metals, metalliods.
In this question, the most possibe defination is that an element is a pure substance
A homogenous mixture is a mixture that is said to have one phase of substance throughout. I.e the comprising substance are all in a single phase.
A solution is the mixture of a solute that is completely dissolved in a solvent.
A heterogeneous mixture is a solution that the substance are not in a single phase.
The answer to this question is option B