I'm glad I don't have to choose.
I probably would choose the yorkie because he/she wants a playmate.
But then again,... young working girl might need the pup too, being alone sucks. Might be comforting and I bet the pup would be spoiled.
I agree with the others who said home visits. Check 'em out. Meet 'n greet, see how they interact with the pup. You're head and heart will tell you what to do after that.