$7$ Multiple Choice $3$ points connected to S$2,$ even though they are both in VLAN $20.$ Which command should be added to F$20/1$ on $51$ to corred the problem?

S$1*$ sh interfaces trunk

Port Mode Encapsulation Status Native vlan

Fa$0/1$ on $802\mathrm{.}1q,$ trunking $40$

Port Vlans allowed on trunk

$Fa\frac{O}{11},20,40,60,80$

Port Vlans allowed and active in management domain

$Fa\frac{O}{11},20,40,60,80$

Port Vlans in spanning tree forvarding state and not proned

S$14$

switchport nonegotiate

$5$ witchport trunk allowed vian add $40$

switchport trunk native vian $80$

$9$

switchport modedynamic auto