Consider the following statements about stationary waves:
$A$. The distance between two adjacent nodes or antinodes is equal to $\frac{\lambda}{2}$ $(\lambda = \text{wavelength of the wave})$.
$B$. $A$ pressure node is always formed at the open end of the open organ pipe.
Choose the correct option from the following:

• A
  Only the statement $A$ is true
• B
  Only the statement $B$ is true
• C
  Both statements $A$ and $B$ are true
• D
  Both statements $A$ and $B$ are wrong