To solve this problem, we need to identify which hormone level triggers ovulation from the Graffian follicle. Let's analyze each option:$\newline \bullet$Option 1: High concentration of Progesterone$\newline$ - Progesterone is primarily involved in maintaining the uterine lining for pregnancy and is not responsible for triggering ovulation.$\newline \bullet$Option 2: Low concentration of LH$\newline$ - Luteinizing Hormone (LH) is crucial for ovulation. A surge, not a low concentration, of LH triggers ovulation.$\newline \bullet$Option 3: Low concentration of FSH$\newline$ - Follicle Stimulating Hormone (FSH) is important for follicle development, but a low concentration does not trigger ovulation.$\newline \bullet$Option 4: High concentration of Estrogen$\newline$ - High levels of estrogen lead to a positive feedback mechanism that results in the LH surge, which triggers ovulation.$\newline$Therefore, the correct answer is Option 4: High concentration of Estrogen.