Under which of the following objectives of Millennium Development Goals, the…

Concept

The Millennium Development Goals (2000–2015) set time-bound, measurable targets. Judging "progress for the world as a whole" means comparing the GLOBAL achievement status of each target against its 2015 benchmark, independent of regional success or failure.

Applying it to these four targets

1. Gender parity in primary and secondary education (MDG 3): achieved at the global/developing-world level — girls' enrolment reached parity with boys.

2. Halving the share of people below the extreme/national poverty line (MDG 1, Target 1.A): met globally, and ahead of schedule — the share living in extreme poverty was halved before 2015.

3. Halting and reversing the spread of HIV/AIDS (MDG 6, Target 6.A): the trend was reversed — new infections fell sharply (roughly 40% from the 2000 peak), so the world moved decisively in the right direction.

4. Halving the proportion of people who suffer from hunger (MDG 1, Target 1.C): the global halving benchmark was NOT reached — the undernourishment share fell from about 23% to about 13%, a large drop but short of half, and progress was the least satisfactory of the four.

Cross-check / contrast

Two of the four targets were fully met globally (poverty share and education gender parity) and one was clearly reversed (HIV/AIDS new infections). Only the hunger target fell short of its global benchmark at 2015, making it the objective on which world-wide progress was least satisfactory.

Hence the correct objective is: reducing by half the proportion of people who suffer from hunger by 2015.