Imports System
Imports System.Text.RegularExpressions

Public Class Test
	Public Shared Sub Main()
Dim input As String = "17.	 Specific heat of certain element is 0.064, its approximate atomic mass is" & vbCrLf &
"1) 100 U	2) 10 U	3) 20 U	4)  Both  2) and 3)"
Dim regex As Regex = New Regex("(?<=\t)[1-4]\)")
Dim result As String = regex.Replace(input, "#")

Console.WriteLine(result)
	End Sub
End Class