IPv6-only application instances must call an IPv4-only internet API without an inbound IPv4 address. Which combination provides the required connectivity?

1. Add an IPv4 default route to an internet gateway without assigning IPv4 addresses.
2. Use an egress-only internet gateway to translate IPv6 into IPv4.
3. Enable DNS64 for the subnet and route the synthesized NAT64 prefix to a NAT gateway.
4. Create a Route 53 AAAA record containing the API IPv4 address unchanged.