Senior high school people's education printing plate mathematics compulsory one chapter three review reference questions group A and the second group are entitled What C to choose? The topic is as follows ABCD starts to move clockwise,

A: op should first increase to the upper left and then move, then decrease until the vertical edge of OP is the smallest, then increase, and then decrease after reaching the upper right. The trajectory is a straight line. mistake

B OP first increases and then decreases, and the trend is the same as that of C, but the trajectory changes linearly around a square or rectangle, which is wrong.

C OP keeps increasing, then reaches the maximum through OP, and then decreases. The traces on both sides are symmetrical and the curves are correct.

D Because the O point is not the left, right, up and down vertex, the OP first becomes larger and then smaller, and then becomes smaller and smaller. The image is asymmetrical, although it is also a curve, it is also an error.

This kind of problem generally does not need qualitative calculation.

I hope it helps you. Thank you.