Which private VLAN can have only one VLAN and be a secondary VLAN that carries unidirectional traffi

Which private VLAN can have only one VLAN and be a secondary VLAN that carries unidirectional
traffic upstream from the hosts toward the promiscuous ports and the gateway?

A.
isolated VLAN

B.
primary VLAN

C.
community VLAN

D.
promiscuous VLAN