In the figure shown, all line segments meet at right angles, and the area of each rectangular region is one-half the area of the next larger region. What fractional part of square region ABCD is shaded?

This choice represents a larger fraction of the square's area than what is logically possible given the relationship between the areas of the rectangular regions. Since the shaded area is derived from a series where each area is half of the preceding one, the calculations yield a more precise value, indicating that 5/16 cannot represent the correct shaded area.

While this fraction is smaller than 5/16, it still overestimates the shaded area when calculated against the total area of square ABCD. The relationship of each rectangular region's area being half of the next does not support this value, as the progression leads to a smaller shaded area than indicated by 9/32.

This fraction suggests an area that is too small given the geometric properties of the configuration. The relationship of areas shows that the shaded portion must be larger than 33/128, as the series of areas calculated results in a greater total for the shaded sections.