Is my analysis of quantum numbers describing the ground state of At correct? Which series of quantum numbers describes the highest (energy) occupied orbital in a ground state of At atom?

a) n = 6, l = 0 
b) n = 6, l = 2 
c) n = 5, l = 2 
d) n = 4, l = 3 
e) n = 6, l = 1 

According to my teacher, the answer is e.

My analysis: 


The electron configuration of At atom: 


$$\begin{aligned}1s^22s^22p^63s^23p^6\ce{3d^10}4s^24p^64\ce{d^10}5s^25p^64\ce{f^14}\ce{5d^10}6s^26p^5
\end{aligned}$$

Knowing for levels 0,1,2,3 correspond to s,p,d,f respectively we can say that: 

a) $$\begin{aligned}6s^2\end{aligned}$$
b) $$\begin{aligned}Nothing \end{aligned}$$
c) $$\begin{aligned}\ce{5d^10}\end{aligned}$$
d) $$\begin{aligned}\ce{4f^14}\end{aligned}$$
e) $$\begin{aligned}\ce{6p^5}\end{aligned}$$

What I thought here first is that d is the answer since 4f14 has the largest number of electrons, and thus will occupy the highest energy around.

Then I saw on another question that the orbitals are filled so that the ones of lowest energy are filled first.

$$1s &lt; 2s &lt; 2p &lt; 3s &lt; 3p &lt; 4s &lt; 3d &lt; 4p &lt; 5s &lt; 4d &lt; 5p &lt; 6s &lt; 4f &lt; 5d &lt; 6p &lt; 7s ...$$

In this case, e is the answer since 6p5 has the highest energy regardless of the number of electrons it is holding?
Yes , there is another name for it (n+l) rule or Aufbau principle

http://en.wikipedia.org/wiki/Aufbau_principle

Even though it is not correct to check this rule at such higher values of Z where the trend sometimes changes due to very less differnce between higher values of shell and orbitals .But if you are a beginner you should not heed to this statement.