To solve this problem, we need to determine when the blood pressure in the mammalian aorta is at its maximum. Let's analyze each option:$\newline \bullet$Option 1: Systole of the left atrium$\newline$ - During the systole of the left atrium, the atrium contracts to push blood into the left ventricle.$\newline$ - This phase does not directly affect the aortic pressure significantly.$\newline \bullet$Option 2: Diastole of the right ventricle$\newline$ - During the diastole of the right ventricle, the ventricle relaxes and fills with blood from the right atrium.$\newline$ - This phase is related to the pulmonary circulation and does not impact aortic pressure.$\newline \bullet$Option 3: Systole of the left ventricle$\newline$ - During the systole of the left ventricle, the ventricle contracts and pumps blood into the aorta.$\newline$ - This is when the blood pressure in the aorta is at its maximum because the forceful contraction of the left ventricle pushes blood into the systemic circulation.$\newline \bullet$Option 4: Diastole of the right atrium$\newline$ - During the diastole of the right atrium, the atrium relaxes and fills with blood from the vena cavae.$\newline$ - This phase does not affect the aortic pressure.$\newline$Therefore, the blood pressure in the mammalian aorta is maximum during the systole of the left ventricle.$\newline$This corresponds to Option 3.