In order, Mount Batur (in front, with the flag), Mount Abang and in the back, exactly behind Mount Abang, the higher Mount Agung volcano (the highest summit in Bali).
Those three volcanoes are almost aligned.
I took the photo from another part of the Batur crater rim (which is the feature in the foreground, with the Indonesian flag).
For more information about those volcanoes, read: