Answer:
Point B is located below the xy-plane. True
Every point with a z value less than 0 is located below the xy-plane.
You can approximate the z value of any point by looking at the yellow arrow in the figure. if it points down the value is negative.
Point C is located behind the yz-plane. True
Every point with a x value less than 0 is located behind the yz-plane.
You can approximate the x value of any point by looking at the green arrow. if the arrow points back the value is negative
