The CompTIA A+ course has four specialist sections - you’ll have to qualify in two of these areas to be A+ competent. This is why, most colleges only offer two of the four in the syllabus. We consider that this isn’t enough - yes you’ll have qualified, but training on all 4 will give you a distinct advantage in your working life, where gaps in your knowledge will expose weaknesses. That’s the reason why you should train in all 4 specialities.