What are the themes that can be exported in a Lightning Bolt Solution?

The correct choice highlights that only Custom Experience Builder themes can be exported as part of a Lightning Bolt Solution. Custom Experience Builder themes are specifically designed to be utilized within the Salesforce Experience Cloud, allowing greater flexibility and customization in creating engaging and branded experiences for users.

The justification for this focuses on the nature of Lightning Bolt Solutions, which are built to streamline and package community templates, components, and assets for rapid deployment. These communities utilize themes developed in Experience Builder to maintain design consistency and adhere to branding requirements.

In contrast, custom themes, stand-alone themes, and pre-existing AppThemes may not meet the standards or restrictions related to the exporting function of Lightning Bolt Solutions. Custom themes created outside of Experience Builder are not compatible for export, while pre-existing AppThemes typically serve a specific purpose and lack the necessary flexibility to fit within the customizable framework required by Lightning Bolt. Thus, Custom Experience Builder themes are the only viable option for effective use within the framework of Lightning Bolt Solutions.