The Diagram Shows the Roads Connecting Four Cities $\mathrm{Y}$ And $\mathrm{Z}$ By Passing Through Exactly Two Cities? (Hint: Write a Matrix

Multiple Choice

The diagram shows the roads connecting four cities.
How many ways are there to travel between cities $\mathrm{Y}$ and $\mathrm{Z}$ by passing through exactly two cities? (Hint: Write a matrix, A, to represent the number of routes between each pair of cities without passing through another city. Then calculate $\mathrm{A}^{2}$ and $\mathrm{A}^{3}$ ) .

A) 11
B) 15
C) 14
D) 13