Which EU Directive aims to harmonize animal research legislation across European countries?

The answer is B, EU Directive 2010/63. This directive is specifically designed to ensure the welfare of animals used for scientific purposes and aims to harmonize legislation across EU member states regarding the use of animals in research. It sets guidelines for the ethical treatment of animals, establishes standards for them, and requires member states to adopt regulations that align with these overarching EU standards.

The directive underscores the importance of the 3Rs principle—Replacement, Reduction, and Refinement—promoting alternatives to animal testing and minimizing the number of animals used in research while improving their care and welfare. Its implementation ensures better consistency and cooperation among countries regarding animal research, facilitating a more unified approach to scientific experimentation.

This regulatory framework is essential for fostering ethical research practices and advancing scientific knowledge while maintaining high welfare standards. The other directives listed do not focus on animal research legislation, thus making them less relevant to this specific context.