Answer: 90° option a
180° option b
Step-by-step explanation: If we do a rotation of 90° about the X point, this means that the angle between the lines XZ and X'Z must be equal to 90°.
The options that have a 90° angle between these two lines are a and c.
And here you can see that, if the rotation is counterclockwise, the option a is a rotation of 90° and option c is a rotation of 270°, while if the rotation is defined clockwise, the option c is 90° and option a is 270°.
Usually, the rotations are defined as counterclockwise, so under this viewpoint, the right answer is option a.
For a 180° rotation the angle between XZ and X'Z' must be equal to 180°, the only option that has a 180° angle is option b, so here b is the answer.
