The answers that are provided for each of the end-of-chapter questions are designed to expand your understanding of the subject matter. The rationale presents knowledge that is just beyond the 210-255 exam scope, because it is this knowledge that a prospective cybersecurity operator should be striving for. 

Some of the rationale and specific examples are not covered directly in this book; there are elements where judgment calls need to be applied, and this will come with practice. The 210-255 exam may well provide examples that aren't in this or any other book; this is the idea – to keep the value of the certification, the questions are held secretly within a tight circle. The idea behind the questions here – and in the mock and the actual 210-255 exam – is to test understanding rather than memorization. Sometimes, an answer will reveal itself by eliminating the options that are definitely irrelevant.

The questions, together with the rationale provided here, should be used to identify where there are weaknesses in your understanding. This can be improved by exploring the Further reading section of each chapter.