Apublic announcement is made about a newly discovered, rapidly spreading virus. the security team immediately updates and applies all its antivirus signatures. the security manager contacts the antivirus vendor support team to ask why one of the systems was infected. the vendor support team explains that a signature update is not available for this virus yet. which of the following best describes this situation?
a. zero day virusb. lack of vendor supportc. untrained usersd. firewall configuration issues