Crayon colored

Ok, so we got one of these worksheets(there was also a car, draogn, some lines, and a house to choose from but I chose this) and the teacher told us that we had to color it but had to include shading. The water took lon cuz I wanted it to be like a sunset and the sky I'm finishing up on, but now I gots a problem.
I don't know what to color the buildings or the top of the brigde. I suppose purple would really stand out but what do you think? What colors would go nicely with reds and oranges?

Worksheet not drawn by me. All rights to Alred Sisley.