**Core Concept**
The CuT 380 A is a type of intrauterine device (IUD) that uses copper as the active component to prevent pregnancy. The life span of an IUD refers to the duration for which it is effective in preventing pregnancy.

**Why the Correct Answer is Right**
The CuT 380 A is a copper-releasing IUD that has been shown to be effective for a period of 10 years. The copper ions released from the IUD interfere with sperm motility and fertilization, making it difficult for the sperm to reach the egg. This mechanism of action is due to the toxic effects of copper ions on sperm and the egg, as well as the disruption of the fertilization process.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the CuT 360 is a different type of copper IUD with a shorter life span of 4 years.
**Option B:** This option is incorrect because the Mirena is a hormonal IUD that releases levonorgestrel, not copper, and has a life span of 5 years.
**Option C:** This option is incorrect because the Nova T is a copper IUD with a life span of 5 years, not 10 years.

**Clinical Pearl / High-Yield Fact**
The CuT 380 A is the only copper IUD that has been shown to be effective for a period of 10 years, making it a popular choice for long-term birth control.

**Correct Answer:** C. 10 years