Which creatures from the alternative upgrade options do you choose?

Is there no one to defend? Well, that's if you have the majority and are attacking. But what if you're in a castle and an army that outnumbers you is attacking? Then it's very useful... and considering that the main hero, for example, from a castle, has cleared out all the 4-5-6-7 level combat units... then skeleton archers + skeletons with shields and zombies will hold out much better.