How many real solutions does a quadratic equation have if its discriminant is zero

If the discriminant of a quadratic is 0 then it means that the quadratic has two non-distinct roots or simply 1 real root.  Thus the answer would be OPTION B

So an example would be  9x² + 12x + 4 = 0 in the form ax² + bx + c
                                        
   the discriminant would be  b² - 4ac = (12²) - 4(9)(4)
                                                           = 0

Now to solve to prove true
         9x² + 12x + 4 = 9x² + 6x  + 6x + 4 = 0

    ⇒ 9x² + 6x  + 6x + 4 = 0
            by factorising
        3x(3x + 2)  + 2(3x + 2)= 0 

         9x² + 6x + 6x + 4 = (3x + 2)² 
         which means it only has one root at x= 2/3