Answer:
Venus, Mercury
Step-by-step explanation:
Scientist exclaimed that there are volcanoes located on those planets, There are more but these are the two I know for now. On Venus, they somehow realized a strong solar beam and saw a huge explosion. They believe it could be found as a volcano. Now how do they know, that I can't answer for you...
I hope these are the answers cause I know that venus is one but I don't know about Mercury.