All the points on the ellipse $\frac{\mathrm{x}^{2}}{2}+\frac{\mathrm{y}^{2}}{1}=1$ are rotated about origin through an angle $\frac{\pi}{4}$ in counter clockwise sense. The equation of ellipse changes to
(a) $3 \mathrm{X}^{2}+3 \mathrm{Y}^{2}+2 \mathrm{XY}=4$
(b) $3 \mathrm{X}^{2}+3 \mathrm{Y}^{2}+\mathrm{X} Y=2$
(c) $3 \mathrm{X}^{2}+3 \mathrm{Y}^{2}-2 \mathrm{XY}=4$
(d) $\frac{X^{2}}{\sqrt{2}}+\frac{Y^{2}}{\sqrt{2}}-X Y=1$