Final answer:
The attack vector that matches the described scenario is Macro-enabled file.
Step-by-step explanation:
The attack vector that best matches the described scenario is 2) Macro-enabled file. Macro-enabled files, such as Word or Excel documents, can contain malicious code that is executed when the file is opened. In this case, the word processing file sent as an email attachment enticed the employee to open it, which triggered the execution of the malicious code.