The normal at a variable point P on an ellipse
a2x2+b2y2=1 of eccentricity e meets the axes of the ellipse in
Q and R , then the locus of the mid-point of QR is a conic with eccentricity e′ such that
a. e′ is independent of e
b. e′=1
c. e′=e
d. e′=e1