Which of the following is an incorrect substitute for saffron?

Chili powder is an incorrect substitute for saffron due to its distinct flavor profile and the fact that it does not mimic saffron's unique characteristics. Saffron is known for its delicate and floral aroma, along with a subtle, complex flavor that contributes to dishes in a way that chili powder cannot replicate. While chili powder can add heat and spice to a dish, it lacks the nuanced taste and coloring properties of saffron.

In contrast, annatto seeds, paprika, and turmeric are often considered for substitution because they can impart color to dishes. Annatto seeds offer a warm, reddish hue akin to that of saffron, while paprika can provide some color variation with its sweet smokiness. Turmeric, while somewhat different in taste, comes close to replicating the yellow-orange hue of saffron. These options might have varying flavor impacts, but they serve to mimic saffron's visual attributes more closely than chili powder does.