**Core Concept**
A dying declaration is a statement made by a person who believes they are about to die, concerning the cause or circumstances of what they believe to be their impending death. This concept is crucial in forensic medicine and law, as it can serve as crucial evidence in criminal investigations.

**Why the Correct Answer is Right**
A dying declaration is a type of exception to the hearsay rule in law, which allows the statement to be admitted as evidence even though it is not made under oath and the declarant is not available to testify. This is because the declarant's statement is considered to be a reliable account of the circumstances surrounding their death, given the circumstances of their dying state. The statement is often made in the presence of a medical professional or other trusted individuals, which adds to its credibility.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because a dying declaration is specifically an exception to the hearsay rule, whereas a confession is a voluntary statement made by a person admitting to a crime.
**Option B:** This is incorrect because a dying declaration is not a type of expert testimony, but rather a statement made by a person who is not an expert in the matter.
**Option C:** This is incorrect because a dying declaration is not a type of hearsay statement that is admissible in court, but rather a specific exception to the hearsay rule.

**Clinical Pearl / High-Yield Fact**
A dying declaration can only be admissible in court if it is made under circumstances that suggest the declarant believed they were about to die, such as being in the presence of a medical professional or having a life-threatening injury.

**Correct Answer: C. Dying declaration is a type of exception to the hearsay rule in law.**