The resting membrane potential of a cell is due to permeability of

**Core Concept**
The resting membrane potential is the difference in electrical charge between the interior and exterior of a cell at rest. This potential is primarily due to the differential distribution of ions across the cell membrane, particularly **potassium (K+)** and **sodium (Na+) ions**. The cell membrane's selective permeability to these ions plays a crucial role.

**Why the Correct Answer is Right**
The correct answer is related to the permeability of the cell membrane to **potassium ions (K+)**. At rest, the cell membrane is more permeable to K+ than to Na+. This permeability allows K+ ions to leave the cell, creating a net positive charge outside the cell and a net negative charge inside, thus generating the resting membrane potential. The **potassium leak channels** are primarily responsible for this permeability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because, although sodium ions are crucial for the action potential, the resting membrane potential is not primarily due to sodium permeability.
**Option B:**
**Option C:**
**Option D:**

**Clinical Pearl / High-Yield Fact**
Remember, the resting membrane potential is crucial for the proper functioning of nerve and muscle cells. Any disruption in this potential can lead to neurological or muscular disorders.

**Correct Answer:** D. potassium ions