C looks suspiciously like the wheels off the nursery 3417 set, but tricky to tell off the photo
is there room for the metal rod on the back?
Thanks for your input Gyps. I've never owned 3147, so I know these particular pieces didn't come from that set. Also, no spot for metal rods.
I would say C are roof lights for old police cars 
Spot on tonguello! I have at least two of those old police cars with no roof lights! Thanks!
Now, how about those helmets? They seem like Playmobil. The fit the children perfectly.