A network technician is planning to update the firmware on a router on the network. The technician has downloaded the file from the vendor's website. Before installing the firmware update, which of the following steps should the technician perform to ensure file integrity?

a. Perform antivirus and anti-malware scans of the file.
b. Perform a hash on the file for comparison with the vendor’s hash.
c. Download the file a second time and compare the version numbers.
d. Compare the hash of the file to the previous firmware update.