**Core Concept**
Emergency contraception refers to the use of drugs or devices to prevent pregnancy after unprotected sex or contraceptive failure. The goal is to prevent ovulation, fertilization, or implantation of the fertilized egg.

**Why the Correct Answer is Right**
The correct answer is likely to be a contraceptive method that is not used for emergency purposes. Among the options, we can consider the following:

* A: **Copper IUD (Intrauterine Device)** is a highly effective emergency contraceptive method when inserted within 5-7 days after unprotected sex. It works by causing a chemical reaction in the uterus that prevents implantation.
* B: **Mifepristone (RU-486)** is an antiprogestin that can be used as emergency contraception when taken within 72 hours of unprotected sex. It works by blocking the action of progesterone, preventing ovulation and fertilization.
* C: **Levonorgestrel (Plan B)** is a progestin-only emergency contraceptive pill that can be taken within 72 hours of unprotected sex. It works by preventing ovulation and fertilization.
* D: **Combined Oral Contraceptive Pills (COCs)** are not typically used as emergency contraception because they require a regular dosing schedule and may not be effective in preventing ovulation after unprotected sex.

**Why Each Wrong Option is Incorrect**
**Option A:** Copper IUD is actually a highly effective emergency contraceptive method, making it an incorrect choice for this question.

**Option B:** Mifepristone is used as an emergency contraceptive when taken within 72 hours of unprotected sex, so it is not the correct answer.

**Option C:** Levonorgestrel is a widely used emergency contraceptive pill, making it an incorrect choice for this question.

**Clinical Pearl / High-Yield Fact**
When considering emergency contraception, it's essential to remember that the sooner the method is used, the more effective it is likely to be. Copper IUDs are particularly effective when inserted within 5-7 days after unprotected sex.

**Correct Answer:** D. Combined Oral Contraceptive Pills (COCs) are not typically used as emergency contraception.