I would also vote "A"
I am not sure what you mean by 17-40 for "long exposures." Of course, all lenses could be used for long exposures. I would get the 17-40 for ultra wide angle landscapes. If you are thinking starscapes, you might want to consider the Rokinon/Samyang 14 mm f/2.8 UMC for an ultrawide angle option. While I have never owned the 17-40, I have definitely seen some great images and the charts are good from f/5.6-f/11, which is perfect for normal landscapes.
But for long exposures, of say waterfalls, you'll be using the 24-70 II a lot of that. Just remember to also buy some good filters. Lots of people talk about the 10 stop filters (Lee Big Stopper, etc). My favorite ND filter is the B+W 6 Stop ND filter. But I also have the B+W 10 Stop ND filter. TDP just did a comparison of 10 Stop ND filters. Singh Ray came out on top.
I started with the 50 f/1.8. I found it to be nicely sharp starting at ~f/2.8. I upgraded to the 50 f/1.4 about 2 years ago. I find it to be sufficiently sharp, at least in the center, starting at f/2. I am now planning on evaluating the Sigma 50 f/1.4 Art. It may be worth the money to me to be sharp at f/1.4. That said, I have heard a number of people state, upon buying the 24-70 II, that they no longer used their 50 f/1.4. So, I might buy the 24-70II first and wait to see if you need the 50 f/1.4.