**Core Concept**
The Millennium Development Goals (MDGs) were eight international development goals for the year 2015 that had been established following the Millennium Summit of the United Nations in 2000. These goals were a set of targets to address issues such as poverty, education, health, and the environment.

**Why the Correct Answer is Right**
The MDGs were based on the United Nations Millennium Declaration, which was signed by 189 countries. This declaration emphasized the need for a global partnership to address the needs of the world's poorest countries and to achieve a more equitable and peaceful world. The MDGs were designed to be measurable, achievable, relevant, and time-bound (MART), with specific targets to be achieved by 2015.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the MDGs were not based on a single document or treaty. Instead, they were a set of goals that were developed through a global consensus-building process.

**Option B:** This option is incorrect because the MDGs were not solely focused on economic development. While economic development was an important aspect of the MDGs, they also addressed issues such as education, health, and the environment.

**Option C:** This option is incorrect because the MDGs were not based on a single country's development strategy. Instead, they were a set of global goals that were developed through a collaborative process involving countries from around the world.

**Clinical Pearl / High-Yield Fact**
The MDGs were replaced by the Sustainable Development Goals (SDGs) in 2015, which have a broader focus on sustainable development and are designed to be achieved by 2030.

**Correct Answer:** D. The MDGs were based on the United Nations Millennium Declaration, which was signed by 189 countries.