Does anyone know how to do this i quite don’t understand?

Which of the following transformations will result in an image that maps onto itself? a. rotate 90 degrees counterclockwise and then reflect across the y axis b. reflect across the x-axis and then reflect across the y-axis c. rotate 90 degrees counterclockwise and then translate 4 units up d. reflect across the x-axis and then reflect again across the x-axis