As shown in the figure, in the cube abcd-a1b1c1d1, P is a moving point in the side bb1c1c. If the distance from P to the straight line BC and the straight line c1d1 is equal, the curve of the trajectory of the moving point P is () A. Straight line B. circle C. hyperbola D. parabola

As shown in the figure, in the cube abcd-a1b1c1d1, P is a moving point in the side bb1c1c. If the distance from P to the straight line BC and the straight line c1d1 is equal, the curve of the trajectory of the moving point P is () A. Straight line B. circle C. hyperbola D. parabola

From the meaning of the title, if the straight line c1d1 ⊥ plane bb1c1c, then c1d1 ⊥ PC1, that is, | PC1 | is the distance from point P to straight line c1d1, then the distance from point P to straight line BC is equal to the distance from it to point C1, so the trajectory of point P is a parabola