The letter $A$ has a vertical line of symmetry and the letter $B$ does not. How many of the letters H L O R X D P E have a vertical line of symmetry?
(A) 1
(B) 2
(C) 3
(D) 4
(E) 5
If a letter is folded along its vertical line of symmetry, both halves of the letter would match exactly.

Three of the given letters, $\mathrm{H}, \mathrm{O}$ and $\mathrm{X}$, have a vertical line of symmetry, as shown.

$$
\begin{array}{llllllll}
H & L & \phi & R & X & D & P & E
\end{array}
$$

ANSWER: (C)