Which of the following adopted a law on data protection and privacy for its citizens known as ‘General Data Protection Regulation’ in April 2016 and started implementation of its from 25th May, 2018?

The correct option is The European Union.

Step-by-Step Explanation:

1. Background & Adoption:
The General Data Protection Regulation (GDPR) is a comprehensive data privacy law. It was officially adopted by the European Union (EU) in April 2016 to replace the older 1995 Data Protection Directive (Directive 95/46/EC).

2. Implementation Date:
After a two-year transition period designed to allow organizations time to comply with the new rules, the GDPR became directly applicable across all EU member states on 25th May 2018.

3. Key Objective:
The regulation was enacted to harmonize data privacy laws across Europe, protect and empower all EU citizens' data privacy, and reshape the way organizations across the region approach data privacy.

Therefore, the regulation was adopted by The European Union.