Which of the following lines, is a normal to the parabola $y^2=16x?$
 

Let $P$ be the point $\left(1 , 0\right) \text{and} Q$ be the point on the locus $y^2=8x.$ The locus of the midpoint of $PQ$ is

The curve described parametrically by, $x=t^2+t+1,y=t^2-t+1$ represents