In the Bohr model of the hydrogen atom, an electron in an allowed circular orbit of radius \(r\) forms a standing de Broglie wave along its orbital circumference. The allowed orbital radii scale with the principal quantum number \(n\) according to \(r_n = n^2 r_1\), where \(r_1\) is the radius of the ground state. Which of the following best describes the shape of a graph of the electron's de Broglie wavelength \(\lambda\) as a function of orbital radius \(r\)?