Questions: What agreement regarding intellectual property did Australia, Canada, Japan, Korea, Morocco, New Zealand, Singapore, and the United States sign?

The answer is: Australia, Canada, Japan, Korea, Morocco, New Zealand, Singapore, and the United States signed the Anti-Counterfeiting Trade Agreement (ACTA), an international treaty to combat global counterfeiting and piracy.

Explanation for each option:

1. The Madrid Protocol: This is an international treaty designed to reduce the costs of international trademark protection. While it is a significant agreement in the realm of intellectual property, the countries listed in the question are not specifically noted for signing this treaty together.

2. The TRIPS Agreement: The Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS) is indeed an international agreement that protects intellectual property. However, it is administered by the World Trade Organization (WTO) and involves a much larger group of countries, not just the ones listed in the question.

3. The Berne Convention: This is an international agreement that protects copyrights. It was first adopted in 1886 and has been signed by many countries worldwide. However, the specific group of countries mentioned in the question is not uniquely associated with signing this convention together.

4. The Anti-Counterfeiting Trade Agreement (ACTA): This is the correct answer. ACTA is an international treaty aimed at establishing international standards for intellectual property rights enforcement to combat global counterfeiting and piracy. The countries listed in the question were among the key participants in negotiating and signing this agreement.