Answer
A. Perfect competition
B. Monopolistically competitive
C. Oligopoly
D. Monopolistically competitive
Work Step by Step
A. There are many sellers for tap water, and the product is not different between the sellers.
B. There are different types of bottled water, and sellers often use advertisements to promote their product
C. In the US, the two main cola producers are Coca Cola and Pepsi. The two own the majority of the market, and there are high barriers of entry into the market.
D. There are many different companies that sell beer, and they use advertisement to stress their differences and promote their products.