Announced to all who attended church that day

Sitting in sacrament the other day I caught Jake picking his nose.  I pulled his hand away and immediately after releasing my hold, his hand returned to his nostril.  In a whisper I said, "Jake, don't pick your nose."  In a whisper he said back, "Don't worry Mom, I'm not gonna eat it.  I'm gonna flick it."  Whispering back to him I replied, "That's still not okay Jake."  Apparently exasperated with the whole whispering scenario he responded in a voice loud enough for the whole congregation to overhear, "Why?  I see you pick and flick your boogers all the time Mom."

What can one respond to that and what volume should accompany the reply?

I decided that silence and no denial would be the best option.