$$7-2=5$$  $$5-2=3.$$ 
Luis has 7 apples and 2 bananas. He gives 2 apples to Yuri who, in return gives bananas to Luis. Then Luis has as many apples as bananas. How many bananas did Yuri give to Luis? 
Options:
A) $$2$$ 
B) $$3$$ 
C) $$4$$ 
D) $$5$$ 
E) $$7$$ 