Segmenting a query with so many columns (data from a long questionnaire)

Hi, Nart , you're only one inch away from goal. After unpivoting the dataset, extract the serial no of questions. i.e. "Q1" from "Q1-A1", "Q1-A2", "Q1-A3" ... a transformed dataset is like this and it's ready for slice and dice from quite a few dimensions, such as index, gender, age, question, etc.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMlTSUfIFYkMzIOEM4hmAeFAamW1IBBvBj9WJVjICstxAPAuQ2UYEzMNlrwGGepDZxlCzjYxgZmMzC7vbsPMRZpvAwsQSZLYxHrOwmYnbj7GxAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Index = _t, gender = _t, age = _t, camp = _t, #"Q1-A1" = _t, #"Q1-A2" = _t, #"Q1-A3" = _t, #"Q1-A4" = _t, #"Q1-A5" = _t, #"Q2-A1" = _t, #"Q2-A2" = _t, #"Q2-A3" = _t, #"Q2-A4" = _t, #"Q2-A5" = _t, #"Q2-A6" = _t, #"Q3-A1" = _t, #"Q3-A2" = _t, #"Q3-A3" = _t, #"Q4-A1" = _t, #"Q4-A2" = _t, #"Q4-A3" = _t, #"Q4-A4" = _t]),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(Source, {"Index", "gender", "age", "camp"}, "Opt", "Answer"),
    #"Inserted Text Before Delimiter" = Table.AddColumn(#"Unpivoted Other Columns", "Question", each Text.BeforeDelimiter([Opt], "-"), type text),
    #"Changed Type" = Table.TransformColumnTypes(#"Inserted Text Before Delimiter",{{"Answer", Int64.Type}, {"Index", Int64.Type}})
in
    #"Changed Type"