You must configure an MX Series device to receive and forward a mixture of single-tag and dual-tag frames on interface xe-0/0/0.
In this scenario what will accomplish goal?

A.
xe-0/0/0 {
flexible-vlan-tagging;
}

B.
xe-0/0/0 {
stacked-vlan-tagging;
}

C.
xe-0/0/0 {
vlan-vci-tagging;
}

D.
xe-0/0/0 {
vlan-tagging;
}