4 random color in C # or vb.net

I have to do a program in either vb.net or c #.

This program is that the computer chooses 1 random color out of 4 and I have to guess the color, but it must tell me that at the end when I chose a color too when I press a button and it will show a message box and tell me the color he chose and say if I'm right or not. Of course it takes a score system if I win: plus 10 points otherwise: minus 5 points.

Can you help me please.

I am open to all possible answers.

Thank you in advance.