If I had to pick just one lens, it would be 20mm - the modern PJ standard. But from your choices . . . 35mm. Wide enough to introduce some interest to the perspective, but not so wide that you have to worry over much about distortions for portraits and such.
If it's a good 20 that's not distortion but exaggerated perspective.
Depends on what your preferred themes are. You might go with the more universal 35mm any day but I would prefer 85mm. With both you might shoot almost all daily street scenes, even the 50mm is a great classic prime you will cherish right only if you have focal lengths around it.