Select the option that expresses the given sentence in passive voice.

The stranger had intended the execution of the plot but the boys thwarted it with their subtlety.

The execution of the plot had been intended by the stranger but it was thwarted by the boys with their subtlety.

The execution of the plot could have been intended by the stranger but it was being thwarted by the boys with their subtlety.

The execution of the plot was intended by the stranger but it had been thwarted by the boys with their subtlety.

The execution of the plot was being intended by the stranger but it has been thwarted by the boys with their subtlety.