What may happen if a dirty brush is dipped directly into an acrylic paint container?

Correct answer: The original colour may become contaminated

The governing concept is preventing contamination of painting materials. A dirty brush carries leftover pigment, water, dust, or mixed colour into the paint container. That material can alter the original hue, reduce its clarity, and make later applications less consistent. Therefore, option C is correct. A dirty brush cannot enlarge the container, make the paint brighter reliably, or stop acrylic paint from drying; the brush should be cleaned before collecting colour.