Question: What is the first episode of the fifth season and the 81st overall episode of the American animated television sitcom "SpongeBob SquarePants" where Sirena Irwin voiced Mama Krabs?
Sentence (from "List of SpongeBob SquarePants cast members"): The regular voice cast consists of Tom Kenny, Clancy Brown, Rodger Bumpass, Bill Fagerbakke, Mr. Lawrence, Jill Talley, Carolyn Lawrence, Mary Jo Catlett and Lori Alan.
Relevant evidence: No