Sum operator ratio computation

If $m$ and $n$ are integers greater than zero with $m < n$, we define $m \nabla n$ as the sum of the integers between $m$ and $n$, including $m$ and $n$. For example, $5 \nabla 8 = 5 + 6 + 7 + 8 = 26$. Then the value of $\frac{22 \nabla 26}{4 \nabla 6}$ is: A) 4 B) 6 C) 8 D) 10 E) 12