Which are correct: <br/><br/>1-About John, I only know that he is a doctor. <br/>1a-As regards John, I only know that he is a doctor. <br/><br/><font color="#4b0082"></font><br/>2-About John, I know nothing.<br/>2a-As regards John, I know nothing.<br/><br/>3-About him, I know that he works for a magazine. <br/>3a-As regards him, I know that he works for a magazine.<br/><br/>4-About John, she told me that he was a doctor. <br/>4a-As regards John, she told me that he was a doctor. <br/><br/>5-About John, she told me nothing <br/>5a-As regard John, she told me nothing.