Your organization has a security requirement: the virtual machines are (Digital Leader)

Correct answer: D) Private Google Access.
Private Google Access allows VM instances with only internal IP addresses (no external IP addresses) to reach Google APIs and services. This feature is useful for accessing Google Cloud services like BigQuery and Cloud Storage without needing to go through a NAT gateway or a VPN. It enables instances to make outbound connections to Google APIs and services over internal IP addresses, without requiring a public IP address or a NAT gateway.

Here's why the other options are less suitable:

Identity-Aware Proxy (IAP): While IAP is excellent for securing access to applications and VM instances, it primarily focuses on authentication and authorization rather than enabling instances without public IPs to access Google Cloud services.
Cloud NAT: NAT gateways are used to enable instances without public IPs to access the internet, but they are not designed to allow instances to access Google Cloud services without a public IP.
VPC Internal Load Balancers: These are used to distribute traffic among VM instances within the same region, but they do not facilitate access to Google Cloud services like BigQuery and Cloud Storage.
Private Google Access is specifically designed to meet the requirement of accessing Google Cloud services without violating the security requirement of not allowing VM instances to access the public internet. It provides a secure and direct path for instances to access Google APIs and services, ensuring that the traffic remains within Google's network and does not expose the instances to the public internet.