Which enzyme/s will be produced in a cell in which there is a nonsense mutation in the lacY gene?

Nonsense mutation is a type of mutation in which a sense codon is changed to a chain-terminating codon. The lac genes encoding enzymes are lac Z, lac Y, and lac A. Transcription of lac Z gene occurs before transcription of lac Y and lac A. A nonsense mutation in the lac Y gene will produce nonfunctional permease. A stop codon will be introduced in the sequence after the lac Z gene. Since only β-galactosidase enzyme is produced and permease and transacetylase enzymes are not produced, lactose is not transported into the cell. Thus, the correct answer is option A.