Teaching is not a(n) ____ which pays very well.
A. post
B. occupation

Note: What’s wrong with A if any, thanks!
By the way, I think "which" needs to be replaced with "that," what do you think?

Question

Teaching is not a(n) ____ which pays very well.
A.	post 
B.	occupation

Note: What’s wrong with A if any, thanks!
By the way, I think "which" needs to be replaced with "that," what do you think?

Answer

A post is something you are appointed to.  An occupation is more of something you choose.  Generally, a person chooses to be a teacher, rather than being assigned to be one.

As for replacing "which" with "that", I would agree with you.  If you cannot remove the part after "which" without destroying the meaning of the sentence, you should use "that" instead.

Evden çıkmadan dil öğrenme fırsatını kaçırmayın. Deneyimli dil eğitmenlerimizden oluşan seçkimize göz atın ve ilk dersinize şimdi kaydolun!