What is interesting to me is that if you consider the surrounding context and also a few other translations of this scripture it begins to seem that what Jesus was asking was actually a rhetorical question.
"Who are faithful and wise servants?" - Contemporary English Version
"Are you a wise and faithful servant of the Lord?" - Living Bible
"A faithful, sensivle servant is one to whom the master can give the responsibility..." New Living Translation
So, that's how I see it.