I'll go with number 4. He looks bored as if he would like to talk, to pass the time. #3 looks like he might give false information just for yucks. #1 looks like a conquistador, so maybe he speaks a different language. #2 doesn't look talkative to me. #5 would be my second choice, as he looks young and eager to make friends. But #6 looks like it's his first day on the job, so I figure he's clueless.