Which volcano erupted for the first time since the 16th century?

The correct answer is Krasheninnikov Volcano in Kamchatka, Siberia, Russia, which erupted for the first time since the 16th century. This significant geological event highlights the ongoing activity in volcanic regions, particularly in areas like Kamchatka, known for its numerous volcanoes due to tectonic plate interactions. The eruption provided valuable scientific insights into the volcanic history and processes of that region, which has been relatively quiet for several centuries. In the broader context, this eruption's timing emphasizes the importance of monitoring volcanic activity, as previously dormant volcanoes can become active due to various geological and environmental changes.

The other options, while notable volcanoes, do not fit the parameters of erupting for the first time since the 16th century. Mount Saint Helens, for example, is well-known for its 1980 eruption following a period of inactivity, while Mount Vesuvius has a well-documented history of eruptions, including the catastrophic one in 79 AD. Vulcan de Fuego is another active volcano with recent eruptions, contradicting the statement regarding historical dormancy.