After Grenfell, the buildings safety act was extended from 6 years to:

The extension of the limitation period for bringing claims under the Buildings Safety Act, which was prompted by the tragic Grenfell Tower fire, reflects an increased emphasis on enhancing building safety standards and ensuring accountability. The original period of six years for claims related to construction defects was deemed insufficient in light of the complexities and the potential long-term implications of safety failures.

By extending the period to 15 years, the legislation aims to provide greater protection for residents and ensure that they have adequate time to pursue claims against those responsible for building safety standards. This change reflects a broader recognition of the need for a more robust framework to address historical building safety issues and to encourage better compliance with safety regulations.

The other options either fall short of or exceed this revised timeframe, not aligning with the updated legislative intent stemming from the issues highlighted by the Grenfell incident.