In the 1990s, a californian was camping in a volcanic area. he died after ignoring posted warnings and sleeping among a stand of dead trees. he was not scalded, not poisoned, not visibly injured, and the campground did not smell bad. what volcanic gas probably killed the camper and the trees?

Carbon dioxide - Carbon dioxide is the only volcanic gas that fits the description. The sulfur gases have bad odors; water vapor could kill only if it were scalding hot; and carbon monoxide is a poisonous gas, but it would change to carbon dioxide in open spaces. In the case above, carbon dioxide seeping upward from a magma chamber had displaced oxygen in the soil around the tree roots and killed the trees (pg 134)

Ithink the answer is a :