Which of the following is the incorrectly labeled classical element? melody—clear, short, balanced phrases rhythm—regular meters and rhythmic patterns harmony—major/minor tonality, commonly used alberti bass form—expanded and experimented with strict form

The incorrectly labelled classical element is the form because Form is the structure of the music. Music is arranged in large musical sections. It is not expanded and experimented in strict form, the rest that are listed like the melody, rhythm and harmony are correct in definition.  

your answer would be d.)