Handwriting analysis has recently been boosted by the invention of 3D micro-profilometry, which can be used to calculate the pressure used at a crossover point such as the center of a figure eight, and to detect the starting and ending points of strokes
not detectable via conventional 2D analysis.
I hate questions like this one! All the choices are wrong and you somehow have to figure out, which is the "least wrong" according to the twisted mind of the writer!
(A) the starting and ending points of strokes - it is not clear whether the points or the strokes are not detectable.
(B) the locations of starting and ending points of strokes that are - even worse: the locations, the points, or the strokes? "That are" is a bit out of place.
(C) where starting and ending points are located, which are - Lack of "the" before "starting" implies that a single stroke may have more than a pair of starting and ending points. I think "which are" should be replaced by "which is", so that the "is" can refer to the "where".
(D) where starting and ending points are located - "not detectable" after "are located" sucks. It just does and you know it.
(E) where the starting and ending points are located, which are - I'd put a "which is" instead of "which are" at the end. Wouldn't make it right though.
I choose (A) from what we have to work with. I am very probably wrong.