The correct answer is B. Order property.
The Order property of a control is a number that represents the order in which the control was added to the form. The control with the lowest Order value is the first control in the tab order, and the control with the highest Order value is the last control in the tab order.
The TabIndex property of a control is a number that specifies the order in which the control is selected when the user presses the Tab key. The control with the lowest TabIndex value is the first control selected, and the control with the highest TabIndex value is the last control selected.
The Tab order property of a form is a list of the controls on the form, in the order in which they will be selected when the user presses the Tab key. The tab order is determined by the Order property of the controls.
The Index property of a control is a number that identifies the control within its container. The Index property is used to access the control programmatically.
For example, if you have a form with three controls, and the controls have Order values of 1, 2, and 3, then the control with the Order value of 1 will be the first control selected when the user presses the Tab key, the control with the Order value of 2 will be the second control selected, and the control with the Order value of 3 will be the third control selected.
The following code snippet shows how to access the control with the Order value of 1:
Control control = form.Controls[1];