GRE is a VPN encapsulation technology that is widely used to transmit packets across heterogeneous...

 GRE Characteristics

GRE doesnotinherently support encryption or authentication. It is a tunneling protocol for encapsulating packets, and data security features must be implemented using other protocols such as IPsec.

Other correct attributes of GRE include:

B.Supports multicast transmission.

C.Acts as a Layer 3 VPN encapsulation technology.

D.Can work with VPN protocols like IPsec for better security.

 HCIP-Datacom-Core Reference

GRE features and limitations are discussed in VPN encapsulation technology chapters​​.