A 60-year-old woman had an ECG recorded at a local emergency department after an automobile accident. Her weight was 70 kilograms (154 pounds), and her aortic blood pressure was 140/80 mm Hg. Use this...

A 60-year-old woman had an ECG recorded at a local emergency department after an automobile accident. Her weight was 70 kilograms (154 pounds), and her aortic blood pressure was 140/80 mm Hg. Use this information and the figure below to answer Questions 41–43.

41. What is the mean electrical axis calculated from standard leads I, II, and III shown in the woman’s ECG?

A) −90 degrees

B) −50 degrees

C) −12 degrees

D) +100 degrees

E) +170 degrees