\what is the purpose of the bcc option in an email? a. to send a backup copy of the message to all email addresses in the address book without concealing the entire list of recipients b. to send a backup copy of the message to all email addresses in the address book without revealing the entire list of recipients c. to send a copy of the message to multiple recipients without concealing the entire list of recipients d. to send a copy of the message to multiple recipients without revealing the entire list of recipients e. to send a message to only one recipient