Select the option that expresses the given sentence in passive voice.
Lee is humming a soothing tune for the masses.
1
A soothing tune is being hummed for the masses by Lee.
2
A soothing tune has been hummed by Lee for the masses.
3
A soothing tune had been hummed for the masses by Lee.
4
A soothing tune was being humming by Lee for the masses.