In a double-slit experiment, monochromatic light of wavelength \(\lambda\) passes through two narrow slits separated by a distance \(d\) and forms an interference pattern on a screen a distance \(L\) away (\(L \gg d\)), with a central bright fringe at the centerline \(y = 0\). A thin transparent film of uniform thickness \(t\) and index of refraction \(n > 1\) is then placed directly over the upper slit. Which of the following correctly describes the shift in the position of the central bright fringe and the change, if any, in the spacing \(\Delta y\) between adjacent bright fringes?