Bad Qubits — Learn Quantum by Doing

Multiple choice

For a graph state |G> on graph G = (V, E), the stabilizer generators are read directly off the graph. What is the generator K_a associated with vertex a (where N(a) is the neighborhood of a)?

K_a = the product of Z_b over all vertices in V
K_a = X_a times X_b over all neighbors b in N(a)
K_a = X_a times the product of Z_b over all neighbors b in N(a)
K_a = Z_a times the product of X_b over all neighbors b in N(a)