‘C. PEM’ is correct SSL .pem files (concatenated certificate container files), are often required for certificate installations when multiple certificates are being imported as one file.

From the Cisco's Devcor training course: There are multiple formats used to create certificate bundles, depending on the format of the certificate. Using a privacy-enhanced mail (PEM) certificate to create bundles is common because of the simple text format of those certificates. To create a PEM certificate bundle, it is enough to copy each certificate in the opposite issuing order in a text file, usually assigning a .pem extension. To create a PEM certificate bundle, copy certificates in reverse order, omitting the final SSL certificate: Root.crt is the root certificate Intermediate1.crt is the intermediate certificate 1 Intermediate2.crt is the intermediate certificate 2 My_certificate.crt is the final requested SSL certificate # Create a certificate bundle mychain.ca-bundle in Linux cat Intermediate2.crt Intermediate1.crt Root.crt > mychain.pem # Create a certificate bundle mychain.ca-bundle in Windows copy Intermediate2.crt + Intermediate1.crt + Root.crt mychain.pem

Selected Answer: C Correct answer: C PEM is right.