Final answer:
The insult intended is that the person is considered too loyal to England.
Step-by-step explanation:
The insult intended when she says, "I didn't think you were a West Briton" is that the person is considered too loyal to England. The term "West Briton" is used to describe someone from Ireland who is seen as being overly supportive of British influence and culture. By saying this, she is implying that he is not patriotic to Ireland and is instead more loyal to England.
The insult intended when someone says, "I didn't think you were a West Briton" is option d) He's too loyal to England. The term West Briton is primarily used in Ireland and tends to be a derogatory term implying that the person is excessively sympathetic or loyal to the British Crown or British cultural norms, at the expense of Irish culture and nationalism.
Hence, when someone is labeled a West Briton, it suggests that they're perceived as being too Anglicized or betraying Irish identity. Therefore answer is d) He's too loyal to England.