What is the meaning of the simile “a bright girdle” in this excerpt from Dover Beach by Matthew Arnold?

The Sea of Faith
Was once, too, at the full, and round earth's shore
Lay like the folds of a bright girdle furled.
But now I only hear
Its melancholy, long, withdrawing roar,
Retreating, to the breath

Question

What is the meaning of the simile “a bright girdle” in this excerpt from Dover Beach by Matthew Arnold?

The Sea of Faith
Was once, too, at the full, and round earth's shore
Lay like the folds of a bright girdle furled.
But now I only hear
Its melancholy, long, withdrawing roar,
Retreating, to the breath

anonymous · Answer

A) It suggests the greatness of an era when England was a world power and commercial success.
B) It critiques the society of the poet's time for conforming too strictly to convention.
C) It refers to the feeling of support and belonging that people once felt in happier times.
D) It highlights the contrast between the vast seascape and the narrow world of the poet.