A conic C satisfies the differential equation (1+y2)dx−xydy=0 and passes through the point (1,0). An ellipse E is confocal with C and has eccentricity 32. Find the equation of the ellipse E.
(1) 3x2+1y2=1
(2) 1x2+3y2=1
(3) 4x2+9y2=1
(4) 9x2+4y2=1