Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions.

In 1812 a young man called James Barry finished his studies in medicine at Edinburgh University. After graduating he moved to London where he studied surgery at Guy’s Hospital. After that the popular young doctor joined the army and over the next forty years had a brilliant career as an army medical officer, working in many far-off countries and fighting successfully for improved conditions in hospitals. It was a remarkable career - made even more remarkable by the discovery upon his death that he was in fact a she, James Barry was a woman.

No one was more surprised at this discovery than her many friends and colleagues. It was true that throughout her life people had remarked upon her small size, slight build and smooth pale face. One officer had even objected to her appointment as a medical assistant because he could not believe that Barry was old enough to have graduated in medicine. But no one had ever seriously suggested that Barry was anything other than a man.

By all accounts Barry was a pleasant and good-humoured person with high cheekbones, reddish hair, a long nose and large eyes. She was well-liked by her patients and had a reputation for great speed in surgery – an important quality at a time when operations were performed without anaesthetic. She was also quick tempered. When she was working in army hospitals and prisons overseas, the terrible conditions often made her very angry. She fought hard against injustice and cruelty and her temper sometimes got her into trouble with the authority. After a long career overseas, she returned to London where she died in 1865. While the undertaker’s assistant was preparing her body for burial, she discovered that James Barry was a woman.

So why did James Barry deceive people for so long? At that time a woman could not study medicine, work as a doctor or join the army. Perhaps Barry had always wanted to do these things and pretending to be a man was the only way to make it possible. Perhaps she was going to tell the truth one day, but didn’t because she was enjoying her life as a man too much. Whatever the reason, Barry's deception was successful. By the time it was discovered that she had been the first woman in Britain to qualify as a doctor, it was too late for the authorities to do anything about it.

What is the main idea of the passage?

The word "principally" is closest in meaning to ____.