Random name-picker with array

I created a program that picks a champion for a role on the game League of Legends using arrays and random numbers.

Is there a quicker and more efficient way of doing this?

There is one form that contains this:

namespace Random_Champ_Picker_V2
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    internal void button1_Click( object sender, EventArgs e )
    {

        arrays array = new arrays();
        if( radioButton1.Checked == true )
        {
            Random T = new Random();
            int t = T.Next( 0, 57 );
            string toop = (string) array.top.GetValue( t );
            textBox1.Text = toop;
        }
        else if( radioButton2.Checked == true )
        {
            Random T = new Random();
            int t = T.Next( 0, 38 );
            string toop = (string) array.jung.GetValue( t );
            textBox1.Text = toop;
        }
        else if( radioButton3.Checked == true )
        {
            Random T = new Random();
            int t = T.Next( 0, 41 );
            string toop = (string) array.mid.GetValue( t );
            textBox1.Text = toop;
        }
        else if( radioButton4.Checked == true )
        {
            Random T = new Random();
            int t = T.Next( 0, 15 );
            string toop = (string) array.marksmen.GetValue( t );
            textBox1.Text = toop;
        }
        else if( radioButton5.Checked == true )
        {
            Random T = new Random();
            int t = T.Next( 0, 18 );
            string toop = (string) array.supp.GetValue( t );
            textBox1.Text = toop;
        }

    }

Class that contains the arrays (I removed most champ names for this post not to be cluttered):

```
namespace Random_Champ_Picker_V2
{
internal class arrays
{
internal string[] supp = new string[] {"Taric","Thresh"};

internal string[] marksmen = new string[]{"Ezreal","Ashe"};

internal string[] top = new string[]{"Zac","Aatrox"};

First of all, you do not need to create an instance of Random class every time.

Then, you may use the ternary operator (the ?: operator) to select the array from which you want to take the element.

And, assuming that you have to take a random element form the array, you may use just a[T.Next(a.Length).

Random T = new Random();
. . .
string[] a = radioButton1.Checked? array.top:
             radioButton2.Checked? array.jung:
             radioButton3.Checked? array.mid:
             radioButton4.Checked? array.marksmen:
             radioButton5.Checked? array.supp:
             null;
if (a != null)
    textBox1.Text = a[T.Next(a.Length)];

StackExchange Code Review Q#60599, answer score: 14