The electron configuration for vanadium is 1s22s22p63s23p64s23d3. To determine the number of valence electrons, we look at the outermost shell, which is the 4s orbital and the 3d orbital.
In the case of vanadium, the 4s orbital has 2 electrons, and the 3d orbital has 3 electrons. Therefore, vanadium has a total of 5 valence electrons.
So, the correct answer is b) 5.