Answer is: B. Hydroxide ions.
An Arrhenius base is a substance that dissociates in water to form hydroxide ions (OH⁻).
For example sodium hydroxide: NaOH(aq) → Na⁺(aq) + OH⁻(aq).
Another example, balanced chemical reaction: Ba(OH)₂(aq) → Ba²⁺(aq) + 2OH⁻(aq).
According to the Arrhenius definition barium hydroxide is base.
Acids and bases when react (neutralisation) produce salt and water.
Add an alkaline compound to raise the pH to 7.2.
Freezing point, boiling point, melting point, smell, attraction or repulsion to magnets, colour change, and many more examples.
No, There are not likely to form in areas that experience a lot of erosion on a daily basis.