J.C. Penney Third-Quarter Profit Rises  CHICAGO (Reuters) - Department store operator J.C. Penney  Co. Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=JCP.N target=/stocks/quickinfo/fullquote"&gt;JCP.N&lt;/A&gt; posted higher third-quarter profit on Tuesday,  helped by stronger sales and fewer markdowns.