How can you set it to untagged from trunk VLAN 99?

If VLAN 99 is set to trunk, how can you set it to untagged from trunk VLAN 99? (If VLAN 99 trunk is set, how to untagged trunk VLAN 99? )
A. switchport access vlan 99
B. switchport vlan 99 access
C. switchport vlan 99 allow access
D. switchport allow access vlan 99