The recommended answer is D. Configure two Dedicated Interconnect connections in one metro (City) and two connections in another metro, and make sure the Interconnect connections are placed in different metro zones.

Reasoning: This option aligns with Google's recommended practices for production-level applications requiring secure, reliable, and high-performance connectivity. Considering the EHR Healthcare case study, which emphasizes stringent requirements for data security and availability, Dedicated Interconnect is the most suitable solution. Configuring multiple Dedicated Interconnect connections in different metros provides geographical redundancy, ensuring business continuity in the event of a regional outage. Placing the connections in different metro zones within a metro further enhances fault tolerance.

The key considerations are:

Production-Level Application: The question specifically mentions following Google's recommended practices for production-level applications. Dedicated Interconnect is designed for such environments, offering high bandwidth and low latency.
Redundancy and High Availability: EHR Healthcare requires robust connectivity to ensure continuous operation. Multiple Dedicated Interconnect connections in different metros provide the necessary redundancy to meet this requirement.
Bandwidth Requirements: Healthcare applications often involve transferring large volumes of data, such as medical images and patient records. Dedicated Interconnect offers the required high bandwidth (10 Gbps or 100 Gbps) to support these demands.

Why other options are not recommended:

A. Configure two Partner Interconnect connections in one metro (City), and make sure the Interconnect connections are placed in different metro zones. While Partner Interconnect offers a lower barrier to entry and is suitable for some use cases, it does not provide the same level of performance, control, and SLA guarantees as Dedicated Interconnect. Partner Interconnect also relies on a third-party provider, which may introduce additional points of failure and potential security concerns. Also the availability is less.
B. Configure two VPN connections from on-premises to Google Cloud, and make sure the VPN devices on-premises are in separate racks. VPN connections are a viable option for less demanding workloads or as a backup solution, but they are not suitable for production-level healthcare applications that require high bandwidth and low latency. VPN connections also introduce encryption overhead, which can impact performance.
C. Configure Direct Peering between EHR Healthcare and Google Cloud, and make sure you are peering at least two Google locations. Direct Peering is primarily intended for large content providers or ISPs that exchange significant volumes of traffic with Google. It does not offer the same level of service guarantees or support as Dedicated Interconnect. Also, Direct Peering is not typically the recommended approach for hybrid connectivity between on-premises systems and Google Cloud for most enterprises, especially when the need for high availability and dedicated bandwidth is paramount.

Therefore, considering the EHR Healthcare case study's requirements for security, availability, and performance, along with Google's recommended practices for production-level applications, Dedicated Interconnect (option D) is the most appropriate choice.

Google Cloud Interconnect, https://cloud.google.com/network-connectivity/docs/interconnect/concepts/choosing-interconnect
Choosing between Partner Interconnect and Dedicated Interconnect, https://cloud.google.com/network-connectivity/docs/interconnect/concepts/partner-dedicated-interconnect