What type of lengths should both primary and secondary piping consist of between containment sumps?

The correct choice emphasizes that both primary and secondary piping should be constructed with continuous lengths between containment sumps. This design approach is crucial for multiple reasons, primarily focusing on minimizing potential leak points and ensuring the integrity of the piping system. Continuous lengths eliminate joints or connections that could serve as points of failure, which is especially important in underground storage tank (UST) systems where leaks can lead to environmental hazards and regulatory non-compliance.

By utilizing continuous lengths, the likelihood of leaks occurring at joints or fittings is significantly reduced, thereby enhancing safety and reliability. This approach also facilitates easier inspection and maintenance, making it simpler to identify any potential issues without having to deal with complex junctions or sections that may require additional attention.

While other options may suggest various configurations, they do not prioritize the critical aspect of minimizing risk and ensuring a seamless system, which is why continuous piping is the standard practice for both primary and secondary systems between containment sumps.