The Cubic Polynomial given here is
x³ - x² - x -3 =0
Rational root theorem :
Consider any polynomial
→ 
So, the factors of this polynomial is those number which divides
.Which are 
Applying the same method the number which divides (-3) are,-3,+3,-1,+1. So By rational root theorem all the factors of this cubic polynomial is
.
Option 1. -3,-1,1,3 is correct option.