unexpected '<' - jak udělat aby to nevadilo

<? $c = $a;
$d = <img src="$a.bmp"> ?> 
<? if ($c < 16) {echo $d} else {Bohužel tam je jenom 15 rybiček, a vy se pokoušíte dostat na tu $a.}  ?>
1=<img src="1.bmp"><br>
2=<img src="2.bmp"><br>
<? echo $a ?>=<img src="<? echo $a ?>.bmp"> ?><br><br>
<form method=get" action="start2.php">
<? $c = $a + $b ; echo $c ?>+<select name="b">
<option>1</option>
<option>2</option>
</select>=<input type="submit" value="OK" style="cursor: url('http://cute-spot.com/cursors/21.ani')">
</form>