Question 2
A circuit in a matroid is a minimal dependent set. In other words, a subset S of the universe U is a circuit if S is not an independent set, but every proper subset of S is an independent set. Which of the following would be a circuit for the graphic matroid?
A cycle on any number of vertices
A path on any number of vertices
A star with at least three leaves
A complete subgraph on 4 or more vertices