A 3%/-year-old healthy boy presents with a history of continuous unsuccessful attempts at toilet training. He experiences urinary incontinence at least once daily and a few nights weekly. He has been continent of stool for the past 2 months. Urine dipstick is negative. The nurse practitioner correctly documents a diagnosis of: O A - age-appropriate bladder control. O B - primary enuresis. O C - secondary enuresis. O D - nocturnal enuresis