An aggregate fruit is one which developed from Multicarpellary syncarppous gynoecium, Complete inflorescence, Multicarpellary superior ovary, Multicarpellary apocarups gynoecium

Multi carpellary: Having many carpels
Apocarpous: The pistil is apocarpous when it has several distinct carpels, each with ovary, style, and stigma.
When many fruits which are small, each being called a fruitlet, develop from a single flower, then such fruit is called aggregate fruit or etaerio of fruitlets. Such fruit develops from multicarpellary, apocarpous and superior or inferior ovary.
So, the correct answer is 'Multicarpellary apocarpous gynoecium'.