The diagram shows a circuit in which all the switches are open.
Which of the following switch positions would give a resistance of 4 W between X and Y ?
| S1 | S2 | S3 | S4 | |
|---|---|---|---|---|
| A | Closed | Open | Open | Closed |
| B | Closed | Open | Closed | Open |
| C | Open | Closed | Open | Closed |
| D | Open | Closed | Closed | Open |