The Bulk API is designed to process massive datasets by breaking them into smaller batches that Salesforce processes asynchronously. When a batch fails with the “Max CPU time exceeded” error, it typically indicates that the complexity of the operations triggered by the record—such as Apex triggers, Flows, or complex sharing calculations—exceeds the 10,000ms limit within a single transaction.
Reducing the batch size is the standard architectural remedy because it reduces the number of records processed in a single transaction, thereby lowering the total CPU time consumed by those records. However, the architect must consider the impact on the overall throughput and execution time.
When batch sizes are smaller, the total number of batches required to process the same dataset increases. For instance, moving from a batch size of 2,000 to 200 for a 1-million-record dataset increases the number of batches from 500 to 5,000. Each batch carries its own overhead for initialization and finalization within the Salesforce platform. Consequently, while the individual batches are more likely to succeed, the total time required to complete the entire job will increase.
The architect should also be aware of the daily limit on the total number of batches allowed (typically 15,000 in a 24-hour period). While Option C mentions API request limits, the Bulk API is governed more strictly by its own batch limits. Option B is less likely because "parallel mode" naturally manages concurrency. Thus, the primary trade-off the architect must present to the business is a gain in reliability (successful processing) at the cost of total duration (increased sync time).