Which of the following best describes an idioventricular rhythm? A. Gradual alteration in the amplitude and direction of the QRS; atrial rate indiscernible; ventricular rate 150 to 250 beats/min B. Rapid, chaotic rhythm with no pattern or regularity C. Essentially regular ventricular rhythm with QRS complexes measuring 0.12 second or greater; atrial rate not discernible; ventricular rate 20 to 40 beats/min D. Regular ventricular rhythm with QRS complexes measuring less than 0.10 second; P waves may occur before, during, or after the QRS; ventricular rate 40 to 60 beats/min