Final answer:
The acts of creating illegal copies of licensed software and using unexpected access to sensitive information to build software (answer choices B and C) are illegal, whereas using Creative Commons licensed software for commercial purposes can be legal if done in accordance with the license terms.
Step-by-step explanation:
Creating illegal copies of licensed software is a form of copyright infringement and is illegal.
Similarly, having unexpected access to sensitive information and using it to build software without permission is a breach of confidentiality and could also be against the law, possibly leading to severe legal consequences such as charges of theft or fraud.
However, using Creative Commons licensed software to create a commercial product is not necessarily illegal, as some Creative Commons licenses do permit commercial use, provided the terms of the license are followed.
Therefore, the correct answer to the question of which of the following acts would engage a computing professional in illegal work is B & C.