**Core Concept**
The AIDS Control Programme in India uses a color-coded system to identify and categorize patients with various sexually transmitted diseases (STDs). This system helps in quick identification and management of patients.

**Why the Correct Answer is Right**
Kit 3 under the AIDS Control Programme is used to collect and store blood samples for HIV testing. The kit is labeled with a white color to indicate that it is used for HIV testing. The white color is a standard color used in the program to signify that the kit is used for HIV testing, thereby avoiding cross-contamination with other STDs.

**Why Each Wrong Option is Incorrect**
**Option A:** Red is not used to signify HIV testing kits. It is often used to indicate kits for other STDs like syphilis.
**Option B:** Blue is not a standard color used for HIV testing kits in the AIDS Control Programme.
**Option D:** Green is not used to signify HIV testing kits, as it is often used for other purposes in the program.

**Clinical Pearl / High-Yield Fact**
It is essential for healthcare workers to be aware of the color-coding system used in the AIDS Control Programme to ensure accurate identification and management of patients with STDs.

**✓ Correct Answer: C. White**