**Core Concept**
Achieving a Net Reproduction Rate (NRR) of 1 is a demographic goal where the average woman has two children who survive to reproductive age, thereby replacing the previous generation. This is crucial for stabilizing population growth. Effective contraceptive methods are essential to reach this goal.

**Why the Correct Answer is Right**
Vasectomy is a highly effective, irreversible male sterilization method that eliminates the risk of pregnancy once performed. It is considered a gold-standard contraceptive method for long-term population control. Vasectomy has a failure rate of less than 1% when properly performed, making it an ideal choice for achieving a low NRR.

**Why Each Wrong Option is Incorrect**
**Option A:** Condoms are effective for individual couples but are not suitable for large-scale population control due to their high failure rate (2-10%) and the need for consistent use.
**Option B:** Intrauterine Contraceptive Devices (IUCDs) are highly effective for women, but their insertion and removal require medical expertise, and they may not be as widely accepted as vasectomy for population control.
**Option D:** Oral contraceptive pills are effective for women but have a higher failure rate compared to vasectomy and require consistent daily use, making them less suitable for achieving a low NRR.

**Clinical Pearl / High-Yield Fact**
Long-term, irreversible male sterilization methods like vasectomy are crucial for achieving a low NRR and stabilizing population growth. They are often overlooked in favor of female contraceptive methods but offer significant benefits for population control.

**✓ Correct Answer: C. Vasectomy**