This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Which disinfectant works by plasma membrane damage? 
Select and explain. 
A. Alcohol, B. Quaternary ammonium compounds, C. Formaldehyde, D. Halogen compounds
B: Quaternary ammonium compounds
Answer: B: Quaternary ammonium compounds 
Explanation: Quaternary ammonium compounds acts by damaging plasma membrane causing leakage of cellular contents. 90% alcohol is effective against non spore forming bacteria, fungi and viruses. It acts by denaturation of bacterial proteins. Chlorine and iodine are halogen compounds used as disinfectants. Chlorine acts by altering cellular components, while iodine inhibits protein function. Formaldehyde acts by inactivation of proteins.