Final answer:
Kathy Selden's bright idea to save Don Lockwood's career in 'Singin' in the Rain' involves overdubbing her own singing and speaking voice over that of Don's co-star Lina Lamont's, transforming a potentially obsolete silent movie into a marketable musical.
Step-by-step explanation:
The question "What bright ideas does Kathy have to save Don's career?" likely refers to the plot of the musical Singin' in the Rain, where Kathy Selden comes up with a plan to save Don Lockwood's career. During a period when the film industry is transitioning from silent movies to “talkies”, Don's latest silent movie is in danger of becoming obsolete due to the poor vocal performance of his co-star, Lina Lamont.
Kathy, a talented singer and actress, suggests that they dub her singing and speaking voice over Lina's in the movie. This would allow the film to be converted into a musical with a pleasing vocal performance, thereby revitalizing Don's career.