**Core Concept**
The Cu T 380A is a type of intrauterine device (IUD) used for contraception. It is a non-hormonal, non-reversible form of birth control that works by creating a local inflammatory response in the endometrium, which prevents implantation of a fertilized egg. The lifespan of an IUD is crucial in determining its effectiveness and the need for replacement.

**Why the Correct Answer is Right**
The Cu T 380A IUD is made from copper, which is toxic to sperm. When inserted into the uterus, the copper releases ions that create a hostile environment for sperm, preventing fertilization. The recommended lifespan of the Cu T 380A is 10 years, after which it may need to be replaced to maintain its effectiveness. This is because the copper may corrode or become less effective over time, reducing its contraceptive efficacy.

**Why Each Wrong Option is Incorrect**
* **Option A:** 5 years - This is incorrect because the Cu T 380A is designed to last for 10 years, not 5. Replacing it too early may not provide the desired level of contraceptive protection.
* **Option B:** 15 years - This is incorrect because there is no evidence to suggest that the Cu T 380A lasts longer than 10 years. Using it beyond this period may increase the risk of complications or reduce its effectiveness.
* **Option C:** Lifetime - This is incorrect because the Cu T 380A is a non-reversible form of birth control, but it is not designed to be a lifetime solution. It may need to be replaced after 10 years to maintain its effectiveness.

**Clinical Pearl / High-Yield Fact**
The Cu T 380A is a highly effective form of birth control, with a failure rate of less than 1%. However, it may not be suitable for everyone, particularly those with a history of pelvic inflammatory disease (PID) or those who are allergic to copper.

**Correct Answer: D. 10 years.**