Answer:
Tap water ⇒ Monopoly
In a monopoly, there is only one supplier of a certain good or service. Tap water is therefore a monopoly as only one provider supplies it.
Bottle water ⇒ Monopolistic competition
In a monopolistic competition, similar but differentiated products are supplied. As bottled water is differentiated by advertising, it must exist in a monopolistic competition.
Cola ⇒ Oligopoly
An oligopoly is controlled by a few firms who have to engage in strategic planning behavior in order to sell their goods. This means that they would either lower prices to match competitors or collude with them to ensure stable prices.
Beer ⇒ Oligopoly
In an oligopoly, the market is controlled by a few firms who have an incentive to collude to set a certain price because a price war would be bad for all the firms involved.