In Pixar's Cars, Lightning McQueen's first sponsor is Rust-eze.
Rust-eze is a bumper-ointment brand whose founders, Rusty and Dusty Rust-eze, discover Lightning after his early racing success. The sponsor's distinctive orange branding appears on Lightning's race car and helps launch his professional career, even though Lightning initially dreams of replacing it with the more prestigious Dinoco sponsorship.
The Rust-eze connection is central to Lightning's character arc. At the beginning, he treats the brand and its owners as stepping-stones to fame. During his stay in Radiator Springs, however, he develops genuine affection for the Rust-eze team and its people. By the end, he chooses to remain with Rust-eze rather than abandon them.
Dinoco is the major alternative sponsor in the film, which makes it the most common wrong answer. It is associated with The King and later becomes connected with Lightning, but it is not his original sponsor.