**Core Concept**
The Millennium Development Goals (MDGs) aimed to improve maternal and child health worldwide. The target to reduce Maternal Mortality Ratio (MMR) was one of the eight MDGs, with a specific goal to reduce the MMR by three-quarters between 1990 and 2015.

**Why the Correct Answer is Right**
The MDG target for reducing MMR was a global effort to decrease maternal deaths due to pregnancy-related complications. To achieve this goal, various strategies were implemented, including improving access to quality maternal healthcare, increasing the number of skilled birth attendants, and enhancing emergency obstetric care. The ultimate goal was to reduce the MMR from 385 deaths per 100,000 live births in 1990 to 70 deaths per 100,000 live births in 2015.

**Why Each Wrong Option is Incorrect**
**Option A:** This option does not specify the target MMR reduction, making it an incomplete answer.
**Option B:** There is no record of a target to reduce MMR by 50% between 1990 and 2015.
**Option C:** The actual target was to reduce MMR by three-quarters, not two-thirds.

**Clinical Pearl / High-Yield Fact**
The MDGs played a crucial role in raising global awareness about maternal and child health, leading to significant improvements in healthcare outcomes worldwide. The MDG target for reducing MMR served as a benchmark for measuring progress towards achieving this goal.

**Correct Answer: A. 2/3 (70 deaths per 100,000 live births)**