To determine the sum of the exterior angle measures of a 100-sided polygon, we start by recalling an important property of polygons:
The sum of the exterior angles of any polygon is always [tex]\(360^\circ\)[/tex], regardless of the number of sides.
This property holds for all polygons, whether they are triangles, quadrilaterals, pentagons, or in our case, a 100-sided polygon.
Therefore, the sum of the exterior angle measures of a 100-sided polygon is [tex]\(\boxed{360^\circ}\)[/tex].
So, the correct answer is:
B. [tex]\(360^\circ\)[/tex]
