Final answer:
The quickest method to transfer a good file to a computer with a corrupt file is by using the c$ administrative share, which allows direct copying over the network.
Step-by-step explanation:
When a help desk technician determines that a user's issue is caused by a corrupt file on their computer, the fastest way to transfer a good file to the computer would likely be to use the c$ administrative share to copy the file.
This method allows the technician to access the computer's hard drive over the network using administrative privileges, which enables the direct copying of the necessary file without requiring setup on the user's part.
Transferring the file via remote assistance is an option but typically is slower and may require the user to perform additional steps.
Attaching the file to an email could also introduce complications such as file size limits or security restrictions. Overall, utilizing the c$ administrative share is commonly regarded as a quick and efficient solution for resolving such an issue.