Ther right answers are the letters "A. Australia" and "C. Penguins".
The explanation for this is that a proper noun is one that particularizes beings by distinguishing them from their species, such as entities, countries, cities, states, continents, planets, oceans, among others. These names are always written with the initial capital letter. In this sentence, the words "Penguins" and "Australia" are the only ones that exert this particularization and were written with the first letter in May.
