Answer
Choice D.
Work Step by Step
If $l=2$, then $m_l$ has 5 possible values:–2, –1, 0, +1, +2. For each of those combinations of $l$ and $m_l$, there are 2 possible spin states: $m_s = \pm \frac{1}{2}$.
There are 10 possible states in this subshell.
Note that in the n = 100 shell, $l$ ranges from 0 to 99, so there are many more additional electron states in the shell.
