A 14-Year-Old Girl Is Brought to by Her Mother Due

A 14-year-old girl is brought to by her mother due to menstrual cycle irregularity. She has menarche at 13, and since that time her period is unpredictable and she has 4 to 5 menstrual cycles per year. when she does have a menstrual period, she bleeds for 7-10 days and occasionally needs to use nearly twice as many tampons a day as her older sister Medical history is unremarkable. BMI is 23 kg/m2. Urine pregnancy test is negative, and a complete blood count is normal
Which of the following is the most likely cause of this patient's irregular bleeding?

A) Elevated serum LH levels
B) Endometrial stimulation by progesterone
C) Excessive peripheral estrogen production
D) Increased FSH secretion
E) Low and irregular GnRH pulses