The equation of the chord of the ellipse $$\frac{x^2}{25} + \frac{y^2}{16} = 1,$$ whose mid-point is  $$(3,1)$$  is: 

A

$$ 48x + 25y = 169 $$

B

$$ 5x + 16y = 31 $$

C

$$ 25x + 101y = 176 $$

D

$$ 4x + 122y = 134 $$