Eclipsing binaries are binary star systems whose members eclipse each other, blocking one another's light and thereby causing the system to look fainter to observers on Earth. Assuming that the eclipsing binary stars are spherical with circular orbits, by number, identify all of the following 5 choices which could influence the light curve of an eclipsing binary: 1) orbital inclination, 2) luminosities of the stars, 3) orbital period, 4) radii of the stars, 5) spectral type of the stars.