$7$ dollars =~ $700$ cents  $(700-6\times90)\div50=3R10$ 
Chloe has＄$$7$$. She is going to buy $$6$$ pens, and each costs $90$ cents. She also buys a certain number of pencils, and each costs $$50$$ cents. How many pencils at most can she buy? (Adapted from 2007 Math Kangaroo Problem, Level 3-4, Question \#4) 
Options:
(A) $$5$$ 
(B) $$4$$ 
(C) $$3$$ 
(D) $$2$$ 
(E) $$1$$ 