Which of the following is the BEST indicator of ovarian reserve?

Measurement of rise in basal FSH is an excellent indicator of ovarian aging. As women age serum FSH concentrations in the early follicular phase begins to increase due to a decline in the number of small follicles secreting inhibin. Day 3 FSH concentration greater than 20 to 25 IU/L is considered to be elevated and is associated with poor reproductive outcome. Measurement of serum E2 levels along with serum FSH adds to the predictive power of an isolated FSH determination. Basal E2 concentration greater than 75 to 80 pg/ml are associated with poor response to ovarian stimulation and pregnancy outcome. Ref: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics By Carl A. Buis