This question came up recently, around the same time I saw a misinterpretation of a 4C bid in competition. I have chosen to elaborate a little more thoroughly in the linked document.
This page will be dedicated to answering all and any bridge related questions. Simply send your question in the contact form (right hand side of the screen). Your question and my reply will be posted on this thread, for the benefit of everybody. After all, you're not the only one thinking about bridge...