The nurse is caring for a 3-year-old client who is two hours postoperative from a cardiac catheterization via the right femoral artery. Which assessment finding is an indication of arterial obstruction?

A. A downward trend in blood pressure and a rapid, irregular pulse may indicate general hemodynamic instability but are not specific to arterial obstruction. B. A moist and oozing dressing can indicate bleeding but does not directly suggest arterial obstruction. C. A weaker pulse in the left foot compared to the right foot could indicate a vascular issue but not necessarily arterial obstruction specifically in the right leg. D. A cool, pale, and blanched right foot indicates compromised blood flow and is a classic sign of arterial obstruction, warranting immediate assessment and intervention.