I am planning on taking Advanced Financial Management as an option but I'm not sure which other Option to take. I'm a full time student at the moment so I do not know what's really trending.
As you stated that your are full time student its mean you have time so other good option will be Advanced Audit and Assurance (P7).
But before selecting P7 You should also think about how comfortable you are with the fundamental areas of audit and assurance.
Before selecting any option paper i'll suggest you that you study articles "Essential underpinning knowledge for Options papers" and "Making the best options choices "
download links of article:
Making the best options choices "http://www.accaglobal.com/content/dam/acca/global/PDF-students/2012s/sa_jul12_options.pdf"
Essential underpinning knowledge for Options papers "http://www.accaglobal.com/content/dam/acca/global/PDF-students/2012e/Essential%20underpinning%20%20for%20Option%20papers.pdf"
As well as following Muhammad's (helpful!) advice, you can also take a look at some of the guidance we provided on this topic in the Learning Community: