Kuruvilla is looking for a new online game to play. During his exploration, the browser gives an indication that there was a network error. Which of the following may have caused this conditiOn

a$.$ The certificate for the site he is accessing has been revoked.

b$.$ OCSP was not able to access the server it was trying to contact.

c$.$ The certificate on the OCSP responder server is in a revoked state.

d$.$ The web server Kuruvilla is trying to access is currently in an offline state