galB is a gene in E. coli which encodes an enzyme that is required for cells to use the sugar galactose .

galB is a gene in E. coli which encodes an enzyme that is required for cells to use the sugar galactose. Suppose that a repressor regulates the expression of the galB gene by binding to the DNA near the promoter of galB and therefore prevents its transcription. Would you expect the repressor to bind DNA in the presence or absence or galactose? Explain your answer.