Find text in word in the cell and replace whole word

How to make that if the word in cell have ab change whole word for ab
find ab replace whole word.JPG

The function find and replace find the word but replace only that part of word.

Sub Test()
    '
    ' Test Macro
    '
    Dim i As Integer
    
    For i = 1 To 2
    
        Columns("A:A").Replace What:=Range("B" & i), _
                               Replacement:=Range("C" & i), _
                               LookAt:=xlPart, _
                               SearchOrder:=xlByRows, _
                               MatchCase:=False, SearchFormat:=False, _
                               ReplaceFormat:=False
    Next i
    
End Sub