Answer: Maintain a target of 35% CPU utilization by locating: cluster-a in zone us-central1-a cluster-b in zone us-central2-a cluster-c in zone asia-northeast1-b cluster-d in zone asia-east1-b

To implement high availability according to Google-recommended practices, it's crucial to distribute your Bigtable clusters across different regions and zones to mitigate the risk of a single point of failure. Option A suggests distributing clusters across US, Europe, and Asia, which provides geographical diversity but does not specifically target the APAC expansion as required. Option B keeps all clusters within the US, which does not address the APAC expansion need. Option C and D both suggest a distribution that includes the APAC region, which is necessary for the expansion. However, Option C includes a cluster in Australia, which is part of APAC, but also includes Europe, which may not be necessary for the immediate APAC expansion. Option D optimally locates clusters in the US and two different zones within Asia (Asia Northeast and Asia East), directly addressing the APAC expansion with high availability by spreading across multiple zones within the target region. Additionally, maintaining a target of 35% CPU utilization is recommended for Bigtable clusters to allow for traffic spikes without performance degradation. Therefore, Option D is the correct choice as it best meets the requirements for both high availability and the APAC expansion.

Author: LeetQuiz Editorial Team