What type of circuit is illustrated?

a closed parallel circuit

a closed series circuit

an open parallel circuit

and open series circuit

This is an open series circuit.

Explanation: It is not an open parellel circuit because if it was, it would not necessarily mean that the circuit is disabled. This circuit is very clearly disabled because it is not parellel, and you can see that the line does not go all the way around. Also, it is obviously not a closed circuit of any kind, as you can see in the lower left of the circuit (closed circuits mean that the little lever therewould not be flipped out, it would be flipped in, completing the rectangularish circuit). The circuit is clearly open in the bottom left, so it cannot be a closed circuit of any kind. So, after using the process of elimination , that only leaves option D). A open series circuit.

Hope this helps! :)