The correct option is C Slope =−t
On comparing y2=12x with standard equation of parabola y2=4ax we get a=3.
The parametric coordinates of point of contact be (at2,2at) i.e (3t2,6t).
Now, the equation of normal will be y+tx=at3+2at i.e y+tx=3t3+6t
Thus, from the equation of normal we found the slope of normal to be −t.