When on defense, be active or passive

Roald Dahl wrote, "The only sensible thing to do when you are attacked is, as Napoleon once said, to counterattack."

That applies in many situations, but not always at the bridge table. When declarer is attacking, sometimes the best defense is to sit back quietly and wait for tricks to appear. In other deals, though, the defenders must actively counterattack.

In today's layout, South is in seven diamonds. What happens after West leads the club queen?