A Company Runs an Application on Amazon EC2 Instances

A company runs an application on Amazon EC2 instances. The application is deployed in private subnets in three Availability Zones of the us-east-1 Region. The instances must be able to connect to the internet to download files. The company wants a design that is highly available across the Region. Which solution should be implemented to ensure that there are no disruptions to internet connectivity?

A) Deploy a NAT instance in a private subnet of each Availability Zone.
B) Deploy a NAT gateway in a public subnet of each Availability Zone.
C) Deploy a transit gateway in a private subnet of each Availability Zone.
D) Deploy an internet gateway in a public subnet of each Availability Zone.