Sub Test()
Dim R As Integer
Dim C As Byte, LastC As Byte
Dim cel As Range
R = ActiveCell.Row
C = ActiveCell.Column
LastC = ActiveCell.Offset(0, 3).Column
Set cel = Range(Cells(R, C), Cells(R, LastC))
With cel
.MergeCells = True
.Interior.ColorIndex = 4
.HorizontalAlignment = xlCenter
.VerticalAlignment = xlCenter
End With
End Sub