Parent and child navigation organization

I am trying to organize the navigation of my product. It has a primary/parent navigation and a child/subnavigation within each primary/parent item. Of the three structure choices I have presented in my photo, could you tell me which you prefer and why? Is there a better way to organize this?

As you can see, Choice A is a parent nav on the lefthand side with child on top. Choice B is an accordion menu. Choice C is a lefthand parent nav with a child nav "drawer" that slides out on hover of the parent nav. Any advice is appreciated! Thanks!