Which of the following transform property value defines a translation, using only the value for the X-axis?

The correct answer is D. translateX(x).

The translate() function takes three values: x, y, and z. The x value specifies the horizontal translation, the y value specifies the vertical translation, and the z value specifies the depth translation.

If you only want to translate an element horizontally, you can use the translateX() function. This function takes one value, which is the amount to translate the element horizontally.

For example, the following code will translate an element 10px to the right:

element.style.transform = "translateX(10px)";

The other options are incorrect because they specify a translation along multiple axes.

• Option A: translate(x) specifies a translation along the x and y axes.
• Option B: translateZ(x) specifies a translation along the x, y, and z axes.
• Option C: translateY(x) specifies a translation along the y axis.