To find the mirror image of a text about the X-axis, we need to flip the orientation of the text vertically. The horizontal positioning remains the same. Here's a step-by-step explanation:

1. Identify the parts of the text that need to be flipped. In this case, it's the entire word "TRIANGLE".
2. When observing a mirror image about the X-axis, the bottom of the text will face upwards and the top will face downwards.
3. Visualize or sketch the mirrored word to ensure the orientation is correct. The letters remain in order, but their vertical alignment is inverted.
4. Select the option that represents this vertical flipping about the X-axis.

In conclusion, the correct mirror image of the text "TRIANGLE" about the X-axis is:

This option shows the vertically flipped version of the original text.