$(12+18)-(29-3)=4$ 
There are $$29$$ students in a certain class. $$12$$ of the students have a sister and $$18$$ of the students have a brother. In this class, only Tania, Barbara, and Anna do not have any siblings. How many students from this class have both a brother and a sister? 
Options:
a: $$$$None 
b: $$1$$ 
c: $$3$$ 
d: $$4$$ 
e: $$6$$ 