From the YouTube description:
Martha Goldman Sigall worked at the Termite Terrace, Leon Schlesinger's Studios in 1939 when Bugs Bunny was created by Ben Hardaway, whose nickname was Bugs.
Ben announced one day that he was going to create a rabbit based on Daffy Duck. Im going to put a rabbit suit on that duck, he said. The result was Porkys Hare Hunt (1938). Chuck Jones then used the rabbit in Presto-O Change-O (1939). Bugs Hardaway then directed Hare-Um Scare-Um (1939). Chuck Jones directed Elmers Candid Camera (1939) with the rabbit.
Tex Avery was assigned to do A Wild Hare (1940) and in that cartoon, the rabbit says Whats up, doc? for the first time, to Elmer Fudd. Martha Goldman asked him why he said that, and Tex said it was a popular thing to say when he was in high school.
In A Wild Hare, they decided to name the rabbit. Tex Avery wanted to call him Jack E. Rabbit. The model sheet listed him only as Bugs Bunny, since Ben Bugs Hardaway had created him. The PR person, Rose Horsely looked at it and recommended Bugs Bunny. Leon Schlesinger liked it and thats how he came to be named.
Martha Sigall was 92 when this video was recorded. She worked in animation for 53 years and when she was 88, published Living Life inside the lines: Tales from the golden age of animation. Its available from Amazon.com. In 2005, she was given a Lifetime Achievement Annie award.
Her son, Bob Sigall, recorded this in her home studio in Culver City California in June of 2009.