Final answer:
Sir John Graeme in "Bonny Barbara Allen" suffers from a broken heart due to unrequited love for Barbara Allen. The correct option is a) A broken heart.
Step-by-step explanation:
In the ballad "Bonny Barbara Allen," the character Sir John Graeme is suffering from a broken heart. This ailment is metaphorical rather than physical and is caused by his unrequited love for Barbara Allen.
Despite the presence of other options like a deadly fever, a sword wound, or a mysterious curse, the text of the ballad specifies that Graeme's condition stems from his emotional and romantic turmoil after feeling rejected by Barbara Allen.
In the ballad 'Bonny Barbara Allen', Sir John Graeme is suffering from a broken heart. The lyrics of the ballad mention the 'sickness of one's heart' as one of the ailments that can afflict someone. Sir John Graeme's unrequited love for Barbara Allen leads to his heartbreak and eventual death.
The correct option is a) A broken heart.