"To inform my audience about the Manhattan Project, which produced the first atomic bomb," is a specific purpose statement for an informative speech about a(n) object. concept. operation. event. narrative.

This statement here is an example of an event

An event

Explanation:

An event is an occurrence or something that took place and hence seen as a happening, and is sometimes of some importance. The Manhattan project, which produced the first atomic bomb is a specific purpose statement talking about an event, where the first atomic bomb was created and one that gave the exact location of the event (Manhattan). An event is expected to have a location and a purpose for the event, and hence this fits as an informative speech about an event.