Final answer:
The solid 3D object produced by rotating the semicircle is a hemisphere with a diameter of 5 units.
Step-by-step explanation:
The solid 3D object produced by rotating the semicircle about line m with a diameter of 5 units is Choice D: A hemisphere with diameter 5 units.
When a semicircle is rotated about a line passing through its diameter, it forms a hemisphere whose diameter is equal to the diameter of the original semicircle.
In this case, the diameter of the semicircle is 5 units, so the resulting solid object is a hemisphere with a diameter of 5 units.