Solution

  1. (implicitly, no path means edge of \(\varnothing\) and self paths are \(cfb\))

  2. Hom objects:

    A B C D
    A cbf cbf cf cf
    B \(\varnothing\) cbf \(\varnothing\) c
    C \(\varnothing\) \(\varnothing\) cbf bf
    D \(\varnothing\) \(\varnothing\) \(\varnothing\) cbf

  3. One subtlety is that we need to say that one can get from any place to itself by any means of transportation for this to make sense. Overall interpretation looks good.