The best startegy to use is to group words that have important features in common (option B), as this way you can associate the meaning with other words that may be easier to memorize and then remember them all more easily.
For example, if you are trying to understand the meaning of: shocked, dismayed, astonished. You can draw a circle and put them all inside the circle; they are all synonyms, so if you know the meaning of 'shocked' which is quite common, then you know the meaning of the other two words (dismayed and astonished).
Option A is too mechanical and time-consuming. Option C is somehow useful, but there is no meaning associated with the words. Option D seems like a good idea, but is time-consuming and lengthy; it will only work if it is detailed with examples, synonyms, antonyms or any category that might be useful for remembering.
To indicate the importance of the discovery he made
C. Skimming allows you to quickly look for details in a text or get the basic idea of its contents.
