Answer:
Musical lyrics.
Explanation:
Hokusai's "The Great Wave" is a famous painting of a sea wave with snowcapped Mount Fiji in the background. This painting would later become the symbol of Japan's transition and new emergence into the world.
Neil MacGregor, the Manager of the British Museum in London presents the painting/ image while also revealing the conditions of how such a painting emerged. And as given in the excerpt, the rhythm of the lines shows that MacGregor used musical lyrics as his outside source.
Thus, the correct answer is the third option.
