What is being compared to the unfolding bud in this poem?

Directions: Read the poem and answer the given question.

UNFOLDING BUD

One is amazed
By a water-lily bud
Unfolding
With each passing day
Taking a richer colour
And new dimensions
One is not amazed,
At a first glance,
By a poem,
Which is as tight-closed
As a tiny bud.
Yet one is surprised
To see the poem
Gradually unfolding,
Revealing its rich inner self
As one reads it
Again
                                                Naoshi Koriyama

The poem 'Unfolding Bud' uses the extended metaphor comparing a poem to a water-lily bud. The poet directly states: 'By a poem, Which is as tight-closed As a tiny bud' - explicitly comparing the poem to a bud. The entire poem explores how both gradually reveal their inner beauty over time. Option A is incorrect - the beginning of a day is not mentioned as a comparison. Option B is incorrect - the lily plant itself is not being compared to the bud; the poem is. Option D is incorrect - the poet's imagination is not what's being compared to the bud.