What is true in order for network traffic to flow between these two virtual private clouds (VPCs)?

An architect designs an application architecture to used two virtual private clouds, one connected to the public internet and one without public internet access.

What is true in order for network traffic to flow between these two virtual private clouds (VPCs)?
A . The virtual private clouds not connected to the public internet must have a VPN gateway.
B. Subnets in both virtual private cloud must use the same CIDR blocks
C. Both virtual private cloud must shared the same security groups
D. A transient gateway must be used to connect the virtual private clouds.

Answer: D

Explanation:

A transit gateway connects VPC resources across multiple regions. VPCs can be connected together with single or multiple transit gateways. As new networks are added to a transit gateway, they are automatically connected to other networks that are also connected to the gateway.