Need Help Modifying Code

The code below was provided to me by a user on the forum. It takes inputs from columns and creates combinations of them (I've also attached the file).

It uses the .CurrentRegion function - however, I'm missing information in column B, so if I start in column A, it'll ignore C and D.

How would I modify the code such that it ignores the column with missing information and skips directly to the next column?

Thank you!!

Option Explicit

Sub ChineseMenu()
    ' shg 2012
    ' Choose one from col A, one from col B, ...
    
    Dim wks         As Worksheet
    Dim avInp       As Variant  ' ragged input list
    Dim nCol        As Long     ' # columns in list
    Dim rOut        As Range    ' output range
    Dim iCol        As Long     ' column index
    Dim aiCum()     As Long     ' *** count of arrangements from right to left
    Dim aiCnt()     As Long     ' count of items in each column
    Dim iArr        As Long     ' arrangement number

    Set wks = ActiveSheet
    
    With wks.Range("A1").CurrentRegion
        .Style = "Input"
        avInp = .Value
        nCol = .Columns.Count
        Set rOut = .Resize(1).Offset(.Rows.Count + 1)
        .Offset(.Rows.Count).Resize(Rows.Count - .Rows.Count).Clear
    End With
    
    ReDim aiCum(1 To nCol + 1)
    ReDim aiCnt(1 To nCol)
    aiCum(nCol + 1) = 1

    With WorksheetFunction
        For iCol = nCol To 1 Step -1
            aiCnt(iCol) = .CountA(.Index(avInp, 0, iCol))
            aiCum(iCol) = aiCnt(iCol) * aiCum(iCol + 1)
        Next iCol
    End With

    For iArr = 1 To aiCum(1)
        For iCol = 1 To nCol
            rOut(iArr, iCol) = avInp((Int((iArr - 1) * aiCnt(iCol) / aiCum(iCol))) Mod aiCnt(iCol) + 1, iCol)
        Next iCol
    Next iArr
    
    rOut.Resize(aiCum(1)).Style = "Code"
End Sub

Chinese Menu.xlsm