GMAT Sentence Correction (SC) | Although ice particles in the upper atmosphere benefit Earth in that

Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation,acting as global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate the destruction of the ozone layer by reacting with chloroflurocarbons (CFC's).

(A) acting as global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate
(B) acting as a global thermostat and thus keeping Earth either from burning