This solution meets the requirements because: • It uses AWS Direct Connect, which provides a dedicated and private connection between the corporate network and AWS, with a minimum bandwidth of 2 Gbps (4 x 1 Gbps). • It uses a Direct Connect gateway, which allows multiple VPCs in different Regions to share the same Direct Connect connection. • It uses a transit gateway, which acts as a network hub that connects multiple VPCs and other networks, such as the corporate network and the inspection VPC. • It uses a transit gateway peering attachment, which enables routing between transit gateways in different Regions. • It uses ECMP routing, which allows traffic to be distributed across multiple paths for higher throughput and redundancy. • It uses an inspection VPC, which hosts the approved firewall and filters traffic between the corporate network and the AWS environment.

i have read the answers several times and the debate is indeed between C and D. But i believe C) is excluded in the end because: 1) even if it is stating that is creating "a new transit gateway for each Region" after few phrases is saying "Connect all the VPCs in the three Regions to the transit gateway". Ups...you cannot connect all the VPCs in all the regions on only ONE transit gateway. Maybe is phrased bad(maybe they wanted to say something like: attach all the vpcs to their corresponding transit gateways in each region) or it's a big clue. And i believe is the clue. 2) in D we have a transit peering which is required by "The solution must give all the VPCs the ability to connect to each other" BUT this can be a benefit in the answer or a hint for actually disqualify the response. It is not saying in the question if traffic between regions should be inspected or not.(and i see that most of the ppl assumed that only traffic between on-prem and aws should be inspected) - this one is very tricky. So, yes i will go in the end with D just because of (1) and consider (2) a strange bonus.

D is the correct answer.

D is the correct answer. You need to peer the transit gateways.

I think the correct answer is D.

C is the right, as D didn't say to Connect all the VPCs in the three Regions to the transit gateway. You have no VPCs connected to the TGW in each region, so C is the right.

D provides transit gateway peering, the others don't, so D

I think the key is the need for connecting all the VPCs in different regions together and you can only accomplish that with the TGW peering in D.

D for sure, C does not provide minimum2 Gbps in case of one DX goes down.

option C - each region has a DXGW but maximum 3 VPC can connect on single DXGW without TGW. Option : D , has TGW with DXGW can connect multiple VPC with TGW peering.