Question

rigid means unbending or resilient which is its antonym?
flexible - bending easily
dull - being boring or uninteresting
vibrant - having many bright colors

Explanation:

The word "rigid" means unbending. The word "flexible" means bending easily, which is the opposite of unbending. "Dull" means boring and "vibrant" means having bright colors, neither of which are antonyms of "rigid".

Answer:

flexible - bending easily