Define a sequence recursively by x_{0}=5 and

x_{n+1}=\dfrac{x_{n}^{2}+5 x_{n}+4}{x_{n}+6}

for all nonnegative integers n. Let m be the least positive integer such that

x_{m} \leq 4+\dfrac{1}{2^{20}}

In which of the following intervals does m lie?

**Answer Choices**

A. [9,26]

B. [27,80]

C. [81,242]

D. [243,728]

E. [729, \infty]