We are given positions of the coordinates of C and D :
"From the origin, point C is 1.5 units to the left and 3 units up."
1.5 units left of the origin is x = negative 1.5 and 3 units up origin is y = 3.
Therefore, first coordinate on the axis is C(-1.5, 3).
"From the origin, point D is 1.5 units to the right and 3 units up."
1.5 units right of the origin is x = 1.5 and 3 units up origin is y = 3.
Therefore, second coordinate on the axis is D(1.5, 3).
We can see than x-coordinates of C and D are opposite in sign.
When we have x-coordinates opposite in sign, it would be reflection over y-axis.
Therefore, correct option is:
D is C reflected across the y-axis; only the signs of the x-coordinates are different for C and D.