How to apply different motivational theories to understand career orientation? "What motivates you towards choosing the career/job orientation you have chosen? Discuss and explain with reference to three of the motivational theories discussed during the course".

I'm used to writing more scientific essays in the field of psychology, but I am finding some difficulty introducing and maintaining this assignment with a more subjective approach. We are expected to keep with APA rules and formatting and stick to a scientific method of writing. Yet if I am to write a theoretical paper, how am I to keep the focus on what motivates me personally?
Assuming the specific case of being "motivated towards a career" rather then simply getting a job to make ends meet, there can be several factors.

Social status is probably the most common pursuit of a career.

Enjoyment, which is the ideal reason for pursuing a career. Usually a career sought for enjoyment is referred to as 'pursuing one's dream'.

Proximity (a.k.a. convenience) is another driving factor. Which could also be considered the "path of least resistance". An example of this is following in your parents' footsteps. Another example could be someone's part-time job turning into a full-time career.

Addition

I found these two article which describes the work of John Holland and his theory of career choice. (not the scientific essay as requested in the comments but perhaps with more time I, or someone else, could elaborate on this topic further. It is definitely a good one)

http://www.psychologytoday.com/blog/mr-personality/201106/the-psychology-career-choices-why-personality-matters

http://www.careerkey.org/choose-a-career/hollands-theory-of-career-choice.html#.U04FZfldXh5