Which of the following letters will look the same even after lateral inversion?

Any image that is formed in a plane mirror is laterally inverted that is the left and the right side of the image get interchanged. 

For example, the sides of the letter L look flipped in the mirror.

However, we can see that the right and left sides of 'T' look exactly the same. That means even after lateral inversion, 'T' will look the same. 

Therefore, we can say that 'T' will be the same even after lateral inversion.