Step 1: Flag the missing key.
No answer was given for this question in the source, so the answer here is worked out from how India's health programmes are linked.
Step 2: Identify the closest overlap.
HIV weakens the immune system, and tuberculosis is by far the most frequent infection that follows in people with HIV. Because of this, TB control and AIDS control programmes in India run joint collaborative activities, sharing diagnostic services, referral systems and trained staff.
Step 3: Compare with the other options.
RCH, MCH services and immunization mainly cover maternal, newborn and child health. They gain from AIDS control mostly through prevention of mother to child HIV transmission, which is a narrower link compared with the constant, programme-wide overlap between TB and HIV care.
Step 4: Conclude.
Extra investment in AIDS control gives its clearest secondary benefit to the National Tuberculosis Control Programme.