Explanation
To allow syslog on an ESXi transport node, the administrator needs to use the esxcli utility to enable the syslog ruleset in the ESXi firewall. The correct syntax for this command is esxcli network firewall ruleset set
-r syslog -e true, where -r specifies the ruleset name and -e specifies whether to enable or disable it. The other options are incorrect because they either use an invalid syntax, such as omitting the ruleset name or using -a instead of -r, or they disable the syslog ruleset instead of enabling it, which is the opposite of what the question asks. References: [ESXi Firewall Command-Line Interface], [Configure Syslog on ESXi Hosts]