Hello, the definition of the word requisite is: made necessary by particular circumstances or regulations. Therefore, in a sense, you can think of the word requisite as 'necessary'. If you look at your choices, replacing 'requisite' with 'necessary' shows that the choice that makes the most sense is 3. That is because it makes sense to say that Nikita didn't get the job because she didn't possess the 'necessary' skills. Meanwhile, in all the other choices, the word necessary doesn't quite fit. After all, it doesn't quite make sense to have a necessary spirit or necessary behavior :)
