A company's virtual private cloud (VPC) is designed with three isolated subnets, each housed in a separate Availability Zone within the same region. The instances within these subnets require external connectivity to retrieve regular updates. Assuming even distribution and moderate levels of outbound traffic, which setup would be the most economical for providing the necessary access?
Provision separate gateways for network address translation in each subnet for dedicated outbound access.
Eliminate the gateways entirely and assign each isolated subnet an Internet Gateway to ensure external connectivity.
Implement scaled-down, self-managed translation instances in each subnet rather than using managed gateways.
Establish a single gateway for network address translation in one Availability Zone and have the other two subnets route their outbound traffic through it.