how to change target platform from anycpu to x86

Question

i have a .ddl problem after deploying my website i searched solution for  2 days now i got onesolution that is i think i need to change my target platform.but did not got anyother platform in my configuration manager  except anypc.

 

below is my configuration manager's screenshot 

 

 

 

so please tell me how can i change target paltfrom

 

thanks in advance