Every detail of the painting is prominent enough to be seen.

Answer: Option B

Prominent : important; famous.
Negligible : so small or unimportant as to be not worth considering; insignificant.
Insignificant : too small or unimportant to be worth consideration.
Trifling : trivial.
Inconspicuous : not clearly visible or attracting attention.

Antonym of Prominent is Insignificant