Correct Answer - Option 4 : 24 units

__Concept:__

Parabola, **y**^{2} = 4ax, where a > 0, then

Length of latus rectum = 4a

Parabola, **y**^{2} = - 4ax, where a > 0, then

Length of latus rectum = 4a

**Calculation:**

Given parabolic equation , y2 = - 24x

On comparing with standard equation , **a = 6 **

We know that , length of latus rectum = 4a

Latus rectum = 4a

⇒ Latus rectum = 4 × 6

⇒ Latus rectum = **24 **units**.**

**The correct option is 4. **