LH surge occurs at

C. i.e. (24 - 36 hours before ovulation) (37-Shaw's 14th/64-Dutta 4th)* LH surge precedes ovulation by 24 to 36 hours (mean 30 hours) and minimum of 75 ng/ml is required for ovulation (37 - Shaw's 14th)* LH levels remains almost static throughout the cycle except at least 12 hours prior to vulation. When it attains its peak, called LH surge (64 - Dutta 4th)* The main function of LH is steroidogenic, but along with FSH. It is responsible for full maturation of the graffian follicle and oocyte and ovulation