Which content type is NOT supported by the Bulk API?

The Bulk API is specifically designed to enable the processing of large volumes of data efficiently, and it primarily supports data formats that are optimized for bulk data transfers. Among the options provided, HTML is not a suitable content type for the Bulk API, as it is primarily used for rendering web pages and is not structured for data interchange in this context.

The Bulk API focuses on CSV, XML, and ZIP_CSV formats because these types are well-suited for large datasets and comply with the required data formats for Salesforce operations. CSV is a common data format that provides a straightforward structure for large data sets with rows and columns. XML is another supported format that allows for complex hierarchical data structures, facilitating the inclusion of nested records. ZIP_CSV allows for compressed data files that can include multiple CSV files for more efficient handling of big data sets, which is beneficial for performance.

In contrast, HTML does not fulfill the requirements for optimal data transfer in bulk scenarios, which is why it’s not supported by the Bulk API. The Bulk API is intended to process raw data rather than content meant for display or presentation.