AMC 12 2020b Problem 14

Bela and Jenn play the following game on the closed interval $[0, n]$ of the real number line, where $n$ is a fixed integer greater than $4$. They take turns playing, with Bela going first. At his first turn, Bela chooses any real number in the interval $[0, n]$. Thereafter, the player whose turn it is chooses a real number that is more than one unit away from all numbers previously chosen by either player. A player unable to choose such a number loses. Using optimal strategy, which player will win the game?

\textbf{(A)} \text{ Bela will always win.} \textbf{(B)} \text{ Jenn will always win.} \textbf{(C)} \text{ Bela will win if and only if }n \text{ is odd.}$$\textbf{(D)} \text{ Jenn will win if and only if }n \text{ is odd.} \textbf{(E)} \text { Jenn will win if and only if } n>8.