Which chamber receives blood from the veins of the systemic circuit?

Right atrium The answer here requires you to know what the systemic circuit is. That's the circuit that takes oxygenated blood from the heart to the rest of the body and then returns the deoxygenated blood to the heart. With that in mind, let's look at the 4 chambers of the heart. Left atrium gets oxygen rich blood from the lungs and pumps it into the left ventricle. So we know this isn't the correct chamber and we can also ignore the left and right ventricles as well since they receive blood from their respective atriums. That leaves only the right atrium and it's definition is Right atrium gets oxygen poor blood from the body and pumps it into the right ventricle. And that does sound like the correct chamber to me. So the answer is "right atrium"