Final answer:
When the Ds element jumps into a gene coding for red pigmentation early in development and then jumps out, the maize kernel phenotype is a variegated kernel color.
Step-by-step explanation:
The maize kernel phenotype when a Ds element jumps into a gene coding for red pigmentation early in development, and then later jumps out is a variegated kernel color. This occurs due to the inactivation of the C' allele in some aleurone layer cells when the Ds gene jumps into the gene, resulting in the cells reverting to producing the brown pigment as directed by the bz allele. When these cells divide, they create clusters of brown cells surrounded by cells with an active C' allele, creating pigment spots or streaks in the kernel.