question: Hint: Please answer the question and provide the correct option letter, e.g., A, B, C, D, at the end.
  Question: Lines $l$, $m$, and $n$ are perpendicular bisectors of $\triangle PQR$ and meet at $T$. If $TQ = 2x$, $PT = 3y - 1$, and $TR = 8$, find $z$.
  Choices:
  (A) 3
  (B) 4
  (C) 5
  (D) 6