$3+5+6+7=21$ 
What is the sum of the digits in the number $$3567$$? (adapted from $$2011$$ Math kangaroo Problems, Level $$1-2$$, Question \#$$7$$) 
1) $$3567$$ 
2) $$35$$ 
3) $$22$$ 
4) $$21$$ 
5) $356$ 