Assertion (A) : Orthocentre of the triangle formed by any three tangents to the parabola lies on the directrix of the parabola
Reason (R) : The orthocentre of the triangle formed by the tangents at ${\mathrm{t}}_1,{\mathrm{t}}_2,{\mathrm{t}}_3$ to the parabola ${\mathrm{y}}^2=4\mathrm{ax}$ is $\left(-\mathrm{a}, \mathrm{a}\left({\mathrm{t}}_1+{\mathrm{t}}_2+{\mathrm{t}}_3+{\mathrm{t}}_1{\mathrm{t}}_2{\mathrm{t}}_3\right)\right)$