Which one of the following options is correct pertaining to the below transformations?
$Na + NH_{3(l)} \longrightarrow$ Coloured solution $\xrightarrow{\text{on standing}} X + Y$

• A

  $A$. Colour of the solution: Yellow

  $X = NaNH_2, Y = \frac{1}{2} H_2$

• B

  $B$. Colour of the solution: Orange

  $X = NaN_3, Y = \frac{9}{2} H_2$

• C

  $C$. Colour of the solution: Blue

  $X = NaNH_2, Y = \frac{1}{2} H_2$

• D

  $D$. Colour of the solution: Red

  $X = NaN_3, Y = \frac{9}{2} H_2$