The noble-gas electron configuration for Titanium (#22) is ______ and has ______ electrons.
a. [Ar] 3424s2 and 4 unpaired electrons.
b. [Ar] 3s23d2 and 2 unpaired electrons
c. [Ar] 3d4 and 4 unpaired electrons
d. [Ar] 3d24s2 and 2 unpaired electrons
e. [Ar] 4d24s2 and 2 unpaired electrons