The maximum number of radio buttons that can be selected within a buttongroup is
1.
2.
5.
all.

1

Explanation:

The maximum number of radio buttons that can be selected within a ButtonGroup is  1.

For example, in the following code segment we create a button group btn_group consisting of 5 buttons.

ButtonGroup btn_group = new ButtonGroup();

btn_group.add(btn_one);

btn_group.add(btn_two);

btn_group.add(btn_three);

btn_group.add(btn_fours);

btn_group.add(btn_five);

Buttongroup ensures that a maximum of one button is selected at any given point of time.

the difference is right there dont you see it