6) The lines $y=5$ and $y=-1$ intersect the curve $y=m \sin \frac{\omega}{2} x + n (m>0, n>0)$ over the interval $\left[0, \frac{4 \pi}{\omega}\right]$ such that the lengths of the chords obtained are equal and non-zero. Which of the following descriptions is correct?
(A) $m \leqslant \frac{3}{2}, n=\frac{5}{2}$
(B) $m \leqslant 3, n=2$
(C) $m>\frac{3}{2}, n=\frac{5}{2}$
(D) $m>3, n=2$
$6 \mathrm{D}$ Hint: The graph of the function $y_{1}=m \sin \frac{\omega x}{2}, x \in\left[0, \frac{4 \pi}{\omega}\right]$ intersects with $y=a$ and $y=-a, 0 \leqslant a3$,
only at the points where $y_{1}=0$.