How many active volcanoes are in Antarctica?
There really is no 100% agreed upon definition of "active" for volcanoes but most people feel that anything that erupted in the past 10,000 yrs is active. If we use that definition then there are lots of active volcanoes in Antarctica.
The last one to erupt was Mt. Erebus which erupted in 2015.
Deception Island is a location where a lot of scientific stations have been established and then subsequently destroyed by volcanic activity. The last eruption there was in 1970.
According to Wikipedia's list of volcanoes in Antarctica there are 8 volcanoes that are known to have erupted in the last 10,000. I have not double checked it but I assume it is mostly accurate.