Question

An example of an aggregate fruit is
(a)Custard apple
(b)Lack of fruit
(c)Mulberry
(d)Pineapple

Answer 1

Hint: This fruit develops from the merger of several ovaries that were separated during a single flower. The stem axis or floral tube, are involved in the formation of fruit.

Complete answer:
Fruit may be a fleshy or dry ripened ovary and its associated parts of a flowering plant. It always contains seeds, which have developed from the enclosed ovule after fertilization.
Most fruits develop from one pistil (ovary). A fruit resulting from the apocarpous gynoecium (several pistils) of one flower could also be mentioned as an aggregate fruit. Multiple fruits, especially the gynoecium of several flowers. When additional flower parts, like the stem axis or floral tube, are retained or participate in fruit formation, as within the custard apple or strawberry, an accessory fruit results.

Additional information:
Custard apple may be a common name for a fruit, and the tree which bears it is Annona reticulata. The fruits differ in shape. They have heart-shaped, spherical, oblong, or irregular shapes of fruit. The dimensions range from 7 to 12 cm (2.8 to 4.7 in), depending on the cultivar. When ripe, the fruit is brown or yellowish, with red highlights and a varying degree of reticulation, depending again on the variability. The flesh varies from juicy and really aromatic to hard with a repulsive taste. The flavor is sweet and pleasant, like the taste of 'traditional' custard.

So, the correct answer is ‘Custard apple’.

Note:
Accessory fruit may be a fruit during which a number of the flesh comes from the tissue exterior to the carpel. The carpel is the "building blocks" of the ovary. Multiple fruits may be a structure formed from the ovaries of several flowers, which may resemble multiple fruits. Compound fruit may be a term sometimes used when it's not clear whether the fruit is an aggregate fruit, multiple fruits, or a simple fruit formed from a compound ovary.