Concept:
NACO is a government organization in India responsible for prevention and control of HIV/AIDS.
NACO stands for:
\[
\text{National AIDS Control Organization}
\]
It works under the Ministry of Health and Family Welfare and focuses on:
• HIV/AIDS prevention
• Awareness programs
• Testing and counseling services
• Treatment and control strategies
Step 1: Analyze option A.
“Nutritional Agent Control Operation” is not the correct expansion of NACO.
Hence, option A is incorrect.
Step 2: Analyze option B.
“National Active Child Organization” is unrelated to NACO.
Hence, option B is incorrect.
Step 3: Analyze option C.
“Natural AIDS Control Organization” is not the official full form of NACO.
Hence, option C is incorrect.
Step 4: Analyze option D.
NACO correctly stands for National AIDS Control Organization.
Hence, option D is correct.
Therefore, the correct answer is:
\[
\boxed{(D)\ \text{National AIDS Control Organization}}
\]