The principle of `common but differentiated responsibilities and respective capabilities` usually comes up in discussions about global climate change, specifically in relation to the reduction of greenhouse gas emissions, which makes option 3 the correct answer.

In option 1, although the principle could theoretically be applied to global health crises like COVID-19 in that different countries may have different capacities for dealing with the situation, this is not the typical usage of the term.

Options 2 and 4, relating to monetary contributions to the International Monetary Fund or United Nations Peacekeeping Operations, respectively, do not commonly refer to this principle either. While it`s true that countries have different fiscal responsibilities and capabilities, the phrase in question is more specifically associated with climate change discussions.

To summarize, the principle underlines the shared obligation of all countries to address environmental destruction while acknowledging that some countries are more economically developed and technologically advanced, thus having greater capability to shoulder more responsibility.