$q,$ is an Application$-$layer protocol used to monitor and manage network devices, and operates on $$ ports, $$ and $$

a$.$ DHCP $($Dynamic Host Configuration Protocol$),$ TCP $($Transmission Control Protocol$),67$ and $68$

b$.$ SNMP $($Simple Network Management Protocol$),$ UDP $($User Datagram Protocol$),161$ and $162$

c$.$ SMTP $($Simple Mail Transfer Protocol$),$ TCP$,25$ and $26$

d$.$ FTP $($File Transfer Protocol$),$ UDP, $20$ and $21$