Final answer:
Intermittent means occurring at irregular intervals, not continuous or steady, so it most nearly means 'periodic'. The correct option is c.
Step-by-step explanation:
The word intermittent means occurring at irregular intervals; not continuous or steady. Therefore, among the given options, the term most nearly means periodic (c), which refers to something happening or appearing at regular intervals. In the context of the excerpts provided, intermittency relates to things like sounds and natural phenomena occurring sporadically, such as the low and distant sounds described, the breeze causing aspen leaves to tremble, or how variable resources like wind and solar energy are subject to periodic availability.