Can't Transform.SetParent in Unity

i have a problem that i don't understand why is happenning and it's driving me mad. I'm trying to code a script to put the player in the car by disabling the third person controller and then Transform.SetParent. Here's the code:

  public ThirdPersonCharacterControl Controller;
public GameObject Player;
public GameObject Car;

public void PutWheel()
{
if(isInteractive)
{
if(isCar)
{
PlacePlaceables();
Controller.enabled = false;
Player.transform.SetParent(Car);
}
}
}


The error is:

Assets/Scripts/Player/Interactible.cs(361,34): error CS1502: The best overloaded method match for UnityEngine.Transform.SetParent(UnityEngine.Transform)' has some invalid arguments

Assets/Scripts/Player/Interactible.cs(361,44): error CS1503: Argument #1' cannot convert UnityEngine.GameObject' expression to type UnityEngine.Transform'


Why is that happening? It doesn't make sense to me because everything seems correct.

1. Change public GameObject Car to public Transform Car to store the car as a reference to its Transform all along, or...
2. Use Player.transform.SetParent(Car.transform) to access the Transform component attached to the car.