Step 1: The Millennium Development Goals (MDGs) set 8 goals for 2015, of which 3 (Goals 4, 5 and 6) are directly health related.
Step 2: Goal 4 is Reduce child mortality, and its target is to reduce the under-five mortality rate by two-thirds between 1990 and 2015.
Step 3: Do not confuse this with Goal 5 (Improve maternal health), whose target is to cut the maternal mortality ratio by three-quarters. The figure for child mortality is two-thirds, so options a, b and d are incorrect.
Step 4: The correct answer is option 3, Two third.