For what you said that you need, option C is the one to get. If you need bigger storage, go with B (minicard for the OS and 500 GB for data). Option A is useful if PC is bumped around a lot, as SSDs are immune to shocks (within reasonable limits), and would need to have sensitive data separated from the OS. That way, if the OS disk fails or is compromised security-wise, the data on the oher disk would be safe.
It all comes down to what will be the use scenario for the system. Pick the one that fits your needs best.