The blackberry is an example of which of the following fruit types?

A blackberry, just like other berries, is a drupelet, also known as a druplet. That is because it consists of numerous subdivisions called drupes and these drupes are conected to build outer shells of fruits like other types of berries. A plum for example is a single drupe, and if many plums actually built a larger fruit together it would be a drupelet.

The answer is option b.