Which option mitigates VLAN Hopping and Double$-$tagging VLAN Hopping Attacks?

$*$

a$)$ Ensuring that the native VLAN of the trunk ports is different from the native VLAN of the user ports

b$)$ Ensuring that the native VLAN of the trunk ports is the same as the native VLAN of the user ports

c$)$ Setting the trunk port to $$off$.$

d$)$ Enabling auto trunking negotiations.