Step 1: Types of IUDs (Intrauterine Devices)
IUDs can be classified into non-hormonal (e.g., Copper-T, Multiload 375) and hormonal (e.g., LNG-20).
Step 2: Identify hormone releasing device.
LNG-20 releases levonorgestrel, a hormone that prevents pregnancy by thickening cervical mucus and inhibiting ovulation.
Conclusion: The hormone releasing IUD is LNG - 20 (Option 4).