MBA is having different specialisations such as Human - resource management, Computer - management, Finance - management, Sales and Marketing management etc and the persual of a particular stream is chosen by the aspirants depending on their passions and interest for a particular stream.
Let me analyse the case of your present assignment. Since you have indicated that you are working as a HR professional in a FMCG company so it would be better on your part to strengthen your skill in the similar line by taking up the course of HR management. This course will provide you different tools for enhancing your managerial - skills and at the same time you will learn how to handle the people having different mind - frames to achieve the common - goals set by the company. With the right practices of the skill by acquiring HR management, you can motivate, encourage and engage the people of different mind- frames to achieve the desired result in terms of the profit of the company.
Supposing that you change your stream other than HR management, you have to readjust with the new environment and sometimes the newly chosen field may not match your likings leading to the greatest setback for your career. Let us understand it in a different way, suppose one is very much interested to acquire the stream of Sales and Marketing and with the consistent labour, one manages to get the distinction marks at the end of the term but all efforts may go in vain if one cannot achieve the target of the company in terms of sales.
So, the final decision has to be taken by judging one's outlook and attitude. Hence, you need to weigh pros and cones before you take any decision with regard to choosing your specialisation course for MBA.