If commonplace and ordinary -> fails to catch our attention Conclusion: there are some things that fail to catch our attention and are miracles of nature.
What's the gap in the argument that the sufficient assumption needs to fill? That some miracles of nature meet the sufficient condition of being commonplace and ordinary.
Our sufficient assumption is some miracles of nature are ordinary and commonplace, so C. When this is the case, then those same miracles of nature also fail to catch our attention, and therefore we get the conclusion that there are some things that are both miracles of nature and fail to catch our attention.