Final answer:
The colors of Serratia marcescens, Micrococcus luteus, and Escherichia coli on agar slants are red, yellow, and white respectively, corresponding to the pigments produced by these bacteria.
Step-by-step explanation:
The colors of Serratia marcescens, Micrococcus luteus, and Escherichia coli on agar slants are distinctive due to the production of various pigments by these bacteria. Serratia marcescens is known for producing a red pigment called prodigiosin, especially when incubated at room temperature, resulting in red colonies. Micrococcus luteus produces a yellow pigment, which gives the colonies a yellow appearance. On the other hand, Escherichia coli is generally not a pigment producer on standard agar, and typically appears as either white or cream-colored colonies. Therefore, the correct answer to the student's question would be option c) Red, Yellow, White.