To solve this problem, we need to identify which sexually transmitted disease (STD) is completely curable when detected early and treated properly. Let's analyze each option:$\newline \bullet$Genital herpes:$\newline$ - Genital herpes is caused by the herpes simplex virus (HSV).$\newline$ - It is a viral infection and currently has no cure, although symptoms can be managed with antiviral medications.$\newline$ - Therefore, genital herpes is not completely curable.$\newline \bullet$Gonorrhoea:$\newline$ - Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae.$\newline$ - It is a bacterial infection and can be completely cured with appropriate antibiotic treatment when detected early.$\newline$ - Therefore, gonorrhoea is completely curable.$\newline \bullet$Hepatitis-B:$\newline$ - Hepatitis-B is caused by the hepatitis B virus (HBV).$\newline$ - It is a viral infection and while there are treatments available to manage the condition, it is not completely curable.$\newline$ - Therefore, hepatitis-B is not completely curable.$\newline \bullet$HIV Infection:$\newline$ - HIV infection is caused by the human immunodeficiency virus (HIV).$\newline$ - It is a viral infection and currently has no cure, although antiretroviral therapy can manage the condition effectively.$\newline$ - Therefore, HIV infection is not completely curable.$\newline$Based on the analysis, the correct answer is Option 2: Gonorrhoea, as it is the only STD among the options that is completely curable when detected early and treated properly.