I took and passed section B, along with A and D, last March and I must say I had great luck with the Land Development Handbook by Dewberry. It turned out to be a wonderful source. Section B is a really difficult test to pass, and I think CLARB is getting more and more into stormwater management programming elements, so it also helped me to research BMPs from the EPA website. Also, if you have any LARE Prep classes in your area, they help immensely.
I am actually gearing up to take C and E in June, any good sources you know for those sections?