LH and oestrogen concentrations are recorded over part of a menstrual cycle. On what day does ovulation take place?
- Aday 7 with LH 10 and oestrogen 30
- Bday 10 with LH 12 and oestrogen 135
- Cday 13 with LH 120 and oestrogen 130
- Dday 16 with LH 20 and oestrogen 25