Step-by-step explanation:
for the relationship of lengths of internal chords the product of both segments of a chord is equal for all intersecting chords.
in our case
(x+8)×8 = 7×16 = 112
8x + 64 = 112
8x = 48
x = 6
so, D-F = x + 8 = 6 + 8 = 14
so, C is correct
