**Core Concept**
The standard normal distribution, also known as the **z-distribution**, is a probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean. In this distribution, the mean is 0 and the standard deviation is 1.

**Why the Correct Answer is Right**
Since the question is incomplete, let's discuss the general properties of the standard normal distribution. The standard normal distribution has a mean of 0 and a standard deviation of 1. It is often used to compare and contrast the distributions of different datasets by standardizing them.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of option A, we can't determine why it's incorrect, but typically, incorrect options might refer to a different type of distribution or incorrect parameters of the standard normal distribution.
**Option B:** Similarly, without the specifics, we can't assess its correctness, but if it mentioned a different mean or standard deviation, it would be incorrect.
**Option C:** If option C discussed a different distribution altogether, such as the **t-distribution** or **F-distribution**, it would not accurately describe the standard normal distribution.
**Option D:** Any option that does not accurately reflect the properties of the standard normal distribution, such as its symmetry or the area under the curve, would be incorrect.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that about 68% of the data falls within one standard deviation of the mean in a standard normal distribution, which is crucial for understanding and interpreting data in medical research.

**Correct Answer:** Correct Answer: D. has a mean of 0 and a standard deviation of 1.