The equation of the chord, of the ellipse \(\displaystyle \frac{x^2}{25} + \frac{y^2}{16} = 1 \), whose mid-point is \( (3, 1) \) is:
\( 5x + 16y = 31 \)
\( 48x + 25y = 169 \)
\( 4x + 122y = 134 \)
\( 25x + 101y = 176 \)