RT-AC68U LAN DHCP DNS only one address

Wondering if I SSH in to the router if there's a .config file that I can add an additional DNS server address so that the system will hand out two DNS servers to the LAN DHCP clients for some redundancy?

I found /etc/dnsmasq.conf had this in it (its only private addresses so I left them in)

dhcp-range=lan,192.168.100.10,192.168.100.253,255.255.255.0,86400s
dhcp-option=lan,3,192.168.100.254
dhcp-option=lan,6,192.168.100.4,0.0.0.0
dhcp-option=lan,15,companyname.internal...

RT-AC68U LAN DHCP DNS only one address