Hi, I'm working on some php code (for multiple choice test questions) which is included with HTML, and I find that pressing the Submit button erases the answer that
was selected in the dropdown menu. Otherwise the code works correctly. HOw can I prevent the Submit button from erasing the answer filled in by the user?

THis is the code:
<form method="post">
<p>1. &nbsp;
Mary &nbsp; 
<SELECT name="question1">
<OPTION value=na>
<OPTION value=A>tell
<OPTION value=B> said
<OPTION value=C>told
<OPTION value=D>says


that she would be late.

	if ($_POST["question1"]=="B") {
 echo '  <td style="height:80px; align : middle">&nbsp; 1. </td> <td style="green">Correct!  <br /> </td> </tr><tr>' ;   
 elseif ($_POST["question1"]=="na")  {
   echo '<td>&nbsp; 1.</td><td> Please answer this question <br /></td> </tr><tr>';

elseif ($_POST["question1"]!=="B")  {
    echo '<td>&nbsp; 1.</td><td style="red"> Mary  said  that she would be late. <br /></td> </tr><tr>';
<input type="submit" value="Submit" />
Thanks, any help appreciated