What would (4,3) be after it is reflected to the y=x

(3,4)

Step-by-step explanation:

The amount of steps applied from the reflection line to the point would be also applied inversely to the image point (after reflection).

From y=x to (4,3), it goes 1 down and also goes 1 right. (NOTE: It does not go down and right. Instead, it goes either down and right)

So now inverse that to make 1 up and also going 1 left.

based on context clues you gave i'm assuming the answer would be c.