Step 1: Ujjwala is a comprehensive scheme of the Ministry of Women and Child Development aimed at prevention of trafficking and the rescue, rehabilitation and reintegration of victims of trafficking and commercial sexual exploitation.
Step 2: Its twin objectives are first to prevent trafficking and second to rescue and rehabilitate those who have already been trafficked. The target group includes women and children who are either vulnerable to or already victims of trafficking for commercial sexual exploitation.
Step 3: Mapping this to the options, the best fit is child trafficking. While the scheme protects women and children broadly, among the choices given trafficking is the central aim, so option b is correct.
Step 4: Child abuse and child labour are addressed by other programmes and laws, and None is wrong because the scheme clearly has a defined purpose. Hence the answer is child trafficking. (Note: the cooking-gas LPG programme of similar name is unrelated to this welfare scheme.)