A thin soap film of uniform thickness \(t\) and index of refraction \(n > 1\) is suspended in air. A beam of monochromatic light of wavelength \(\lambda_0\) is incident on the top surface of the film at an angle of incidence \(\theta\) relative to the normal. An experimenter measures the optical path difference \(\Delta L\) between the wave reflected from the top surface and the wave reflected from the bottom surface as \(\theta\) increases from \(0^\circ\) (normal incidence) toward \(90^\circ\) (grazing incidence). Which of the following best describes the graph of the optical path difference \(\Delta L\) as a function of the incident angle \(\theta\)?