To accurately answer your question regarding how paragraph 4 refines the central idea in the article "Why Journalism Has a Gender Problem," I would need the specific content or context of that paragraph. However, based on the options provided, the most likely way a paragraph can refine a central idea is by offering facts or statistics that help prove the central claim.
So, if paragraph 4 presents relevant facts or statistics related to gender issues in journalism, then the correct response would be:
It provides facts or statistics that help prove the central claim.
If you have the specific content of paragraph 4, I could provide a more definitive answer.