2. The difference between a virus and a Trojan horse is that... (a) ...a Trojan Horse attaches itself to another executable file and usually replicates itself many times, but viruses do not attach themselves to other files and do not replicate. (b) ...a virus attaches itself to another executable file and usually replicates itself many times, but Trojan Horses do not attach themselves to other files and do not replicate. (c) ... a virus usually disguises itself as a useful software app but a Trojan Horse does not. (d) ... there is no significant difference between Trojan Horses and viruses