Código HTML:
<select name="select1" class="form"> <option value="1">A</option> <option value="2" >B</option> <option value="3">C</option> </select>
Código PHP:
<?php
session_start();
$_SESSION['select1'] = $_POST['select1'];
?>
Código PHP:
<?php
session_start();
echo $_SESSION["select1"]
?>