Okay, let's tackle this question. The user wants to know which IUCD acts for 10 years. The correct answer is the copper IUD, specifically the CuT 380A. I need to explain why that's the case.

First, the core concept here is about intrauterine contraceptive devices (IUCDs). There are two main types: copper IUDs and hormonal IUDs. Copper IUDs release copper ions which are toxic to sperm and eggs, creating an inflammatory response that prevents fertilization. They have a longer duration because they don't rely on hormones degrading over time.

Why is the correct answer right? The CuT 380A is known to last up to 10 years. The copper ions create a local inflammatory reaction that's spermicidal and prevents implantation. The structure of the device allows it to maintain its copper content over a decade without significant degradation.

Now, the wrong options. Hormonal IUDs like Mirena (levonorgestrel) last 3-5 years. They release hormones that thin the endometrium and thicken cervical mucus. Progestin-only options like Liletta or Skyla have shorter durations. The copper IUDs with lower copper content, like CuT 200, last only 5 years. Other options might include LNG IUDs which are shorter-term.

Clinical pearl: Remember that copper IUDs are non-hormonal and longer-lasting. The 10-year duration is a key point for exams. Students often confuse the durations between copper and hormonal types. Mnemonic: "Copper for ten, hormones for five."

**Core Concept**
The question tests knowledge of intrauterine contraceptive devices (IUCDs), specifically their duration of efficacy. Copper IUDs (e.g., CuT 380A) and hormonal IUDs (e.g., levonorgestrel) differ in mechanism and longevity. Copper IUDs act via a non-hormonal inflammatory response, while hormonal IUDs rely on progestin release.

**Why the Correct Answer is Right**
The **Copper T 380A** IUD is effective for **10 years**. It releases copper ions that create a local inflammatory reaction, impairing sperm motility, preventing fertilization, and altering the endometrium to inhibit implantation. Its copper content remains stable over a decade, ensuring sustained contraceptive efficacy without hormonal degradation.

**Why Each Wrong Option is Incorrect**
**Option A:** Hormonal IUDs (e.g., Mirena, Liletta) last **3–7 years**, depending on the model.
**Option B:** The CuT 200 (older copper IUD) lasts **5 years** due to lower copper content.
**Option C:** Progestin-only IUDs like Skyla last **3 years**, while others like Jaydess last **4 years**.
**Option D:** Incorrect duration for any IUD type (e.g., 6 years for non-existent models).

**Clinical Pearl / High-Yield Fact**
**"Copper for ten, hormones for five"**: Copper IUDs (CuT 380A) last **10 years**, while hormonal IUDs (e.g., levonorgestrel)

✓ Correct Answer: C. Cu-T 380A