Monochromatic light of wavelength \(\lambda\) passes through an aperture system and forms a light intensity pattern on a viewing screen located at a distance \(D\) from the aperture. The relative light intensity \(I/I_0\) as a function of position \(y\) on the screen is shown in the graph. Which of the following claims correctly identifies the aperture configuration responsible for this pattern and accurately predicts how the intensity pattern changes if a second identical slit is added parallel to the first at a center-to-center distance \(d > a\)?