The diagram depicts a steel wire fixed at one end and kept under tension at the other end by a weight suspended over a pulley. A vibration generator is connected to the wire close to the fixed end. A stationary wave with one loop is formed. The frequency of the vibration generator is $f$. Which frequency should be chosen to form a stationary wave with two loops?
- A$\frac{f}{4}$
- B$\frac{f}{2}$
- C$2f$
- D$4f$