I believe the answer is C
Water and carbon dioxide are usually the most abundant gases emitted during basaltic volcanism.
If AE is x+50 then the whole thing must be x=50, If a portion of that, CE, is x+32, then the rest of it, AC, must be x+18, because no matter what X is, 32+18=50.
Hopes this helps mate :)
Answer:
otayy, leo.
the oldest mountain, we can say its been around for a while now so it would make sense as to why it would be leo. since its been around the earth has changed and moved shifting plates etc, this takes time. making leos answer make more sense. again im not sure abt this response but this answer (leo) should be right