Different software vendors have different methods of identifying a computer used to activate software. However, a common component used in software activations is a hardware key (or hardware and software key). This key is a hash value generated based on the hardware (and possibly software) installed on the system.
For example, when Microsoft software is activated on a computer, the software generates an installation ID that consists of the software product key used during the installation and a hardware key (hash value generated from the computer's hardware). The installation ID is submitted to Microsoft for software activation.
Changing the hardware on a system can change the hash key which makes the software think it is installed on another computer and is therefore not activated for use on that computer. This is most likely what has happened in this question.
Incorrect Answers:
A: It is very unlikely that the binary files used by the application have been modified by malware. Malware doesn't modify application binary files.
B: A backup image of the system was restored onto the new hardware. Therefore, the software configuration should be the same as before. It is unlikely that blocked ports preventing remote attestation is the cause of the problem.
C: A backup image of the system was restored onto the new hardware. If the restored image backup was encrypted with the wrong key, you wouldn't be able to restore the image.
References:
https://technet.microsoft.com/en-us/library/bb457054.aspx