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CEMC Gauss (Grade 8), 1999

Combinatorics Difficulty 2.0 Junior Find the answer Canada

André is hiking on the paths shown in the map. He is planning to visit sites $A$ to $M$ in alphabetical order. He can never retrace his steps and he must proceed directly from one site to the next. What is the largest number of labelled points he can visit before going out of alphabetical order?

(A) $6$ (B) $7$ (C) $8$ (D) $10$ (E) $13$

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