Option B, "Save Apex errors in a custom object, and allow access to this object for reporting," is the recommended approach for reporting errors from an Apex job that creates leads in Salesforce.

Here's why:

Custom Object for Storing Errors: Using a custom object to store errors allows you to capture and retain detailed information about lead creation failures. You can create fields on the custom object to store relevant error messages, timestamps, and other related data.

Accessibility for Reporting: By allowing access to this custom object, the business team can easily view and report on lead creation failures. They can run reports, create dashboards, or use other reporting tools within Salesforce to analyze and monitor the errors.

Auditing and Tracking: Storing errors in a custom object provides an audit trail of lead creation failures, which can be valuable for debugging and improving the lead creation process over time.