One
If you use the right hand rule for these problems, you usually make your fingers and thumb sit at right angles to each other. What each of the two fingers means and that related to the thumb is a different story. All you have to understand at this point is that all three are mutually perpendicular.
That makes C the answer.
All the other choices don't make that clear.
Two
This is a straight definition question. The definition says exactly what D says.