B&C is going to be Structures (bridges, culverts retainingwalls)... misc infrastructure gantries, posts etc. Buildings too but to a lesser extent.
Technical questions are just going to be related to that background. Knowledge of structure design and asset management. General and knowledge of or at least awareness of the governing NR standards (of which there are a lot) would be helpful.
Have been in that industry for a few years. Hope that helps.