Final answer:
Will Parker is the character in 'Oklahoma!' who exclaims excitement upon returning to see Ado Annie by saying "Whoa, Suzanna! Yoohoo, Ado Annie, I'm back!".
Step-by-step explanation:
In the musical Oklahoma!, it is the character Will Parker who exclaims, "Whoa, Suzanna! Yoohoo, Ado Annie, I'm back!" This exclamation marks his return and his excitement to see his love interest, Ado Annie. The musical itself was groundbreaking for its time, directed by Rouben Mamoulian who was given complete control over the production.
An unusual move then, which together with casting an unknown ensemble made the success of the show even more extraordinary. Oklahoma! was distinctive for its focus on regular people and its unconventional beginnings with Aunt Eller on stage, signifying a departure from the norms of musical theatre where star power and glamorous settings were the norms.