GTM irule CNAME filter

I would like to block GTM from any response except WIP type A.I tried to disable bind in DNS profile but it gives timeout for clients want is not good. I have created irule for listener. So clients have blank respond from GTM, no AAAA, CNAME or ANY in respond.

when DNS_REQUEST {
  if {!([DNS::question type] eq "A") }  {
    DNS::answer clear 
    DNS::return
 }
 }