**Core Concept**
IL-2 receptor inhibitors are a class of immunosuppressive drugs used to prevent rejection in organ transplantation. These drugs target the interleukin-2 (IL-2) receptor, which is crucial for T-cell activation and proliferation. By inhibiting the IL-2 receptor, these drugs suppress the immune response and reduce the risk of transplant rejection.

**Why the Correct Answer is Right**
Basiliximab and Daclizumab are both monoclonal antibodies that bind to the CD25 subunit of the IL-2 receptor. By binding to CD25, these antibodies prevent IL-2 from interacting with its receptor, thereby inhibiting T-cell activation and proliferation. This mechanism of action makes Basiliximab and Daclizumab effective IL-2 receptor inhibitors, commonly used in organ transplantation to prevent rejection. The IL-2 receptor is a heterotrimeric protein complex consisting of three subunits: alpha (CD25), beta (CD122), and gamma (CD132). Basiliximab and Daclizumab specifically target the alpha subunit, which is essential for IL-2 binding.

**Why Each Wrong Option is Incorrect**
**Option A:** Basiliximab is indeed an IL-2 receptor inhibitor, but this option is incomplete because it does not mention Daclizumab, which is also an IL-2 receptor inhibitor.
**Option B:** Daclizumab is also an IL-2 receptor inhibitor, but this option is incomplete because it does not mention Basiliximab, which is another IL-2 receptor inhibitor.

**Clinical Pearl / High-Yield Fact**
Both Basiliximab and Daclizumab are used to prevent rejection in kidney transplantation. They are typically administered as a single dose or multiple doses before and after transplantation, depending on the specific treatment protocol.

**Correct Answer:**
✓ Correct Answer: C. Both 1 & 2