The correct option is B Concerned with
The option with the opposite meaning is the correct one.
The
underlined word 'enamoured' means 'to be filled with love for', or have a lot of admiration for. The king was fond of his own voice.
Option A: This option is similar in meaning, being fond of means 'having admiration' for someone. Hence A is incorrect.
Option C: 'Obsession' is vaguely similar in meaning to the underlined word. The former refers to a fixation or a passion, the latter refers to fondness. Hence it isn't opposite in meaning and C is incorrect.
Option D: To imbue means 'to inspire someone with a feeling or a quality', it doesn't have an opposite meaning. Hence D is also incorrect.
Option B: 'concerned with' means 'worried about', for example, 'the king was concerned about his queen's expenses.' It is most opposite in meaning to the underlined word, hence B is correct.