Step 1: Understanding the Question.
The National AIDS Control Programme (NACP) spends money on blood safety, counselling and testing centres, condom promotion, STI clinics and laboratory strengthening. The question asks which other national programme gains a secondary or indirect benefit from this spending.
Step 2: Key Formula or Approach.
A secondary dividend means a benefit that was not the direct target of the money, but happens anyway because the two programmes share infrastructure, staff, or patients. Tuberculosis is the most common opportunistic infection in people living with HIV, so the two programmes are closely linked at the field level.
Step 3: Detailed Explanation.
As NACP strengthens diagnostic laboratories, counselling services, and referral systems for HIV positive patients, the same infrastructure and trained staff end up screening and managing a large number of HIV associated tuberculosis cases. This cross referral and shared laboratory capacity is the reason NACP investment gives a real secondary boost to the National Tuberculosis Control Programme. RCH and MCH services deal mainly with maternal and child health and immunization deals with vaccine preventable disease, and while HIV testing can occur in these settings too, the strongest and most direct secondary link recognized in public health planning is with TB control, because of the high rate of HIV-TB co-infection.
Step 4: Final Answer.
The National Tuberculosis Control Programme benefits most directly as a secondary dividend of NACP investment.
\[ \boxed{\text{National Tuberculosis Control Programme}} \]