An instrument has two strings. Both have the same length and are uniform. One of the strings is under twice as much tension as the other and also twice the mass of the other. Then which of the following statements is true? (a) The more massive string has a resonant frequency √2 times the other frequency. (b) The frequencies and wavelengths on the two strings are equal but the velocity of the wave is less on the more massive string than on the other. (c) Both strings vibrate at the same frequency but the more massive string has a longer wavelength. (d) Both strings vibrate with the same frequency and have the same wave-length and the same wave velocity.