**Core Concept**
The Cu-T 380A is a type of intrauterine contraceptive device (IUCD) that contains copper and is designed for long-term contraception. It works by causing a local inflammatory response in the uterus, which prevents sperm from fertilizing an egg.

**Why the Correct Answer is Right**
The Cu-T 380A is a T-shaped IUCD with a copper wire coil that has a total surface area of 380 mm². This increased surface area allows for more copper ions to be released, which in turn enhances the contraceptive efficacy. The Cu-T 380A is effective for up to 10 years due to its unique design and copper content, making it an ideal option for women seeking long-term contraception. The copper ions released from the device cause a local inflammatory response, which prevents sperm from penetrating the cervical mucus and fertilizing an egg.

**Why Each Wrong Option is Incorrect**
**Option A:** Cu-T 200 B has a copper surface area of 200 mm², which is significantly less than the Cu-T 380A. As a result, it is not as effective and has a shorter duration of action, typically up to 4 years.
**Option B:** Nova-T is a type of IUCD that contains copper and is effective for up to 5 years. It has a copper surface area of 380 mm², but it is not as effective as the Cu-T 380A due to its different design and shape.
**Option D:** Multi Load-250 is a type of IUCD that contains copper and is effective for up to 5 years. It has a copper surface area of 250 mm², which is less than the Cu-T 380A, making it less effective and not suitable for long-term contraception.

**Clinical Pearl / High-Yield Fact**
It is essential to note that while the Cu-T 380A is an effective form of long-term contraception, it may not be suitable for all women, particularly those with a history of pelvic inflammatory disease (PID) or those who are at risk of PID. Regular follow-up and monitoring are crucial to ensure the continued effectiveness of the device.

**✓ Correct Answer: C. Cu-T 380A**