In a murder trial, which person testifying to the jury is classified as an eyewitness? The medical examiner who found poison in the victim's stomach
An expert discussing evidence collected during an investigation
A defendant's best friend, who was out of town when the crime was committed
A person who claimed to see a car of a certain make/model leaving the scene of a crime

A person who claimed to see a car  of a certain make/model leaving the scene of a crime.

Explanation:

Key words to the

"See"

"leaving the scene of a crime."

Eyewitnesses have a firsthand glimpse of events that occurred and they usually have to have seen something that has occurred to be considered a eyewitness, in this case the person who saw the Make/Model of the car that left the crime scene has some claims that can be used to find the criminal and also when the eye witness sees the car they can  tell which direction it went in to give a bit of a clue(although this depends in certain situations). The eye witness  can also be anyone who was anywhere near the crime scene when it happened or even a little bit after it happened.

D. A person who claimed to see a car of a certain make/model leaving the scene of a crime

Explanation:

It is D because it would be the closest possible lead for finding who did the crime. Anyone around the time of the murder and anyone going in and out at the time is a suspect, even the eyewitness. If the eyewitness saw someone leaving the location moments before it was reported, that would be suspicious.

(lol among us vibes. it hyped me up for this moment.)

The medical examiner who found poison in the victim's stomach

It would not be this one because they were called after the crime took place, the medical examiner only saw the aftermath of said way to k!ll the person.

An expert discussing evidence collected during an investigation

The expert collected data of the crime scene after it had happened. Otherwise, this would not have been possible. So, they were not an eyewitness since they were not present at the time.

A defendant's best friend, who was out of town when the crime was committed

How would the addressed person out of town see the crime scene? Maybe they were threatened to leave the city? Anyway, it just would not make since for the best friend to be an eyewitness at the time of the crime if they were miles away.

the scientific method.