How Many Radio Buttons Can Be Selected at the Same

Multiple Choice

How many radio buttons can be selected at the same time as the result of the following code?
Hours = new JRadioButton("Hours") ;
Minutes = new JRadioButton("Minutes") ;
Seconds = new JRadioButton("Seconds") ;
Days = new JRadioButton("Days") ;
Months = new JRadioButton("Months") ;
Years = new JRadioButton("Years") ;
TimeOfDayButtonGroup = new ButtonGroup() ;
DateButtonGroup = new ButtonGroup() ;
TimeOfDayButtonGroup.add(hours) ;
TimeOfDayButtonGroup.add(minutes) ;
TimeOfDayButtonGroup.add(seconds) ;
DateButtonGroup.add(days) ;
DateButtonGroup.add(months) ;
DateButtonGroup.add(years) ;

A) 1
B) 2
C) 3
D) 4