How to make random Reflection for a ball with c # code?

How to make random Reflection for a ball with c # code?

I am making android game in unity it is a bout ball hit a wall then
reflect to player and the player should press on right button(cube) of 4
button(cubes) ->(up,under,right,left) to reflect the ball to wall and if
he press on wrong button the ball do not reflect and the player lose
chance of 3 chances , and the player have 3 chances if he lose it the game
stop
so -i want c# script to make the ball reflect randomly in 4
position(up,under,right,left)
and -other one to fixed if the player press on right button or no
and -other one to make 3 chances and if he lose it the game stop
please help me,and sorry to prolong
regards