Final answer:
To produce a neutral blond on prelightened pale yellow hair, a blue-violet base toner should be used to neutralize yellow tones and balance the color.
Step-by-step explanation:
When seeking to achieve a neutral blonde tone on prelightened pale yellow hair, the most suitable base toner to use would be blue-violet. The color wheel and color theory are essential for understanding how toners work in hair coloring. Since pale yellow is the underlying pigment after bleaching, a blue-violet toner would be used to neutralize the yellow tones and achieve a more natural, neutral blond color. The blue in the toner will cancel out any remaining yellow hues, while the violet balances the overall shade to prevent it from becoming too ashy or platinum.