## **Core Concept**
The question assesses knowledge of contraceptive methods and their failure rates, expressed in terms of the number of pregnancies per 100 users over a one-year period. The failure rate is a critical measure for evaluating the effectiveness of various contraceptive techniques.

## **Why the Correct Answer is Right**
The correct answer includes contraceptive methods with a failure rate of less than 5 per 100 users in a year.
- **a) Copper-T (Intrauterine Device)**: Highly effective with a failure rate of about 0.8-2.2 per 100 users in the first year.
- **d) OCP (Oral Contraceptive Pills)**: When used perfectly, the failure rate is less than 1 per 100 users in a year, making it very effective.
- **e) Tubectomy (Tubal Ligation)**: Considered nearly 100% effective with a failure rate of about 0.5-1.5 per 100 users.

## **Why Each Wrong Option is Incorrect**
- **Option B: Vaginal sponge**: The vaginal sponge has a higher failure rate, approximately 9-12 per 100 users, which does not meet the <5 criterion. - **Option C: Condom**: The typical use failure rate for condoms is around 13-14 per 100 users, which is higher than 5. ## **Clinical Pearl / High-Yield Fact** A key point to remember is that the effectiveness of contraceptive methods can vary based on "perfect use" versus "typical use." For example, OCPs are very effective with perfect use but have a higher failure rate with typical use due to factors like missed pills. ## **Correct Answer: D. a, d, e**