From the following partial code listing, identify the name(s) of eventhandler method(s) that would need to be written. To what object(s) are they wired?

public class Question System.Windows.Forms.Form { private private System.Windows.Forms.Label labell; System.Windows.Forms.TextBox txtBxActivity; System.Windows.Forms.CheckBox ckBxSwim; System.Windows.Forms.CheckBox ckBxSnorkel; private private private System.Windows.Forms. TextBox txtBxResult; // Colon indicates items missing. private void InitializeComponent ( ) { this.label1 = new System.Windows.Forms.Label ( ); this.ckBxSwim = new System.Windows.Forms.CheckBox(); this.ckBxSnorkel = new System.Windows.Forms.CheckBox(); this. 1stBxEvents. SelectedIndexChanged += new System. EventHandler (this.1stBxEvents_SelectedIndexChanged); // Colon indicates items missing. this.label2.Size = new System.Drawing.Size (120, 24); this.txtBxResult. Location = new System.Drawing. Point (-2, 240);