Valve that guards the right auriculoventricular aperture is:

The correct option is B Tricuspid valve
The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps called the tricuspid valve. As the atria fill to capacity, the tricuspid valve opens to allow blood to flow from the right atrium into the right ventricle. As the ventricles contract, the tricuspid valve shuts tightly to prevent blood from flowing back into the right atrium.

Coronary valve is a valve at the entrance of the coronary sinus into the right atrium. Located on the left side of the heart, the mitral valve is bicuspid, having two cusps or leaflets.

The mitral valve separates the left atrium and left ventricle.

The semilunar valves act to prevent backflow of blood from the arteries to the ventricles during ventricular diastole and help maintain pressure on the major arteries.