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Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

In Carl's pencil case there are nine pencils. At least one of the pencils is blue. In any group of four pencils, at least two have the same colour. In any group of five pencils, at most three have the same colour. How many pencils are blue?

(A) $1$ (B) $2$ (C) $3$ (D) $4$ (E) More information needed

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