As we all know, from Standard 1 onwards NCERT Books forms an essential part of the CBSE curriculum. Basically, NCERT books are a good source of to the point information. From the NCERT Books anyone can understand the concepts very easily and in a very comprehensive manner. In fact, for every topper the basic pillar of their success mantra is NCERT Books.
Once you are thorough with the subject and have a decent grasp on its fundamentals, it will not be an exaggeration to state that with a bit of innovativeness from your side, you can attempt a question to a certain satisfactory level even if you have not prepared the topic very well.
That means that you do not have to worry about leaving a single question in the mains paper and should target to attempt 100% of the paper.
Since the market is filled with sociology optional books and materials in abundance for each topic and micro topic, it is very easy for fresh aspirants to get confused with respect to which sources to target. It is not uncommon to see aspirants hoarding up piles of books and then losing confidence in their preparation.
One of the reasons behind sociology being one of the most popular optionals in UPSC is that the sociology optional syllabus is comparatively less than other optional subjects and it is easier to manage it with the general studies preparation.