সঠিক উত্তর হচ্ছে: ৭
ব্যাখ্যা: The seven Open Systems Interconnection layers are:\nLayer 7: The application layer. ...\nLayer 6: The presentation layer. ...\nLayer 5: The session layer. ...\nLayer 4: The transport layer. ...\nLayer 3: The network layer. ...\nLayer 2: The data-link layer. ...\nLayer 1: The physical layer.