The core concept here is to identify the word related to 'volcano'. 'Volcano' is associated with the idea of an eruption. Among the options, 'C. Eruption' directly relates to the action that happens in a volcano, which is the correct answer. 'A. Boundary' refers to a limit or edge, 'B. Drifting' implies movement without a clear direction, and 'D. Wander' means to walk around slowly without any clear purpose. These options are not directly related to the concept of a volcano.