Which volcano is noted as the largest plug dome volcano in the world?

Lassen Peak is recognized as the largest plug dome volcano in the world due to its unique geological formation and substantial size. Plug dome volcanoes are characterized by their steep, conical shape and are formed from the slow extrusion of viscous lava that is too thick to flow easily. This results in the lava building up near the vent, creating a dome-like structure.

Lassen Peak exhibits these characteristics prominently, making it an excellent representation of plug dome volcanism. In addition to its physical structure, Lassen Peak has a rich volcanic history, including significant eruptions in the early 1900s that helped to shape the landscape we see today.

The other choices represent different types of volcanoes or are not classified as plug dome volcanoes. For example, Mount St. Helens is known for its explosive eruptions and is a stratovolcano, while Mount Rainier and Mount Shasta are also stratovolcanoes known for their height and glacial features, rather than the dome shape specific to plug dome volcanoes. This understanding highlights why Lassen Peak stands out as the largest plug dome volcano worldwide.