Im getting this error CS0246

It says this error CS1031: Type expected and i dont know what to do or change so it is okay. Here is my script thanks for the help.

public class Targetting : MonoBehaviour {
public List targets;
private Transform myTransform;
public Transform selectedTarget;

// Use this for initialization
void Start () {
targets = new List();
selectedTarget = null;
AddAllEnemies();
myTransform = transform;
}
public void AddAllEnemies()
{
GameObject[] go = GameObject.FindGameObjectsWithTag("Enemy");
foreach(GameObject enemy in go)
AddTarget(enemy.transform);
}
public void AddTarget(Transform enemy) {
targets.Add(enemy);
}
private void SortTargetsByDistance()
{
targets.Sort(delegate(Transform t1, Transform t2){
return(Vector3.Distance(t1.position, myTransform.position).CompareTo(Vector3.Distance(t2.position, myTransform.position)));
});
}

private void TargetEnemy()
{
if(selectedTarget == null){
SortTargetsByDistance();
selectedTarget = targets[0];
}
else{
int index = targets.IndexOf(selectedTarget);
if(index < targets.Count - 1){
index++;
}
else{
index = 0;
}
DeselectTarget();			
selectedTarget = targets(index);

}
		SelectTarget();
}
private void SelectTarget(){
selectedTarget.renderer.material.color = Color.red;
		
		PlayerAttack pa = (PlayerAttack)GetComponent("PlayerAttack");
		pa.target = selectedTarget.gameObject;
}
	
private void DeselectTarget(){
		
selectedTarget.renderer.material.color = Color.blue;
		selectedTarget = null;
}		
// Update is called once per frame
void Update () {
if(Input.GetKeyDown(KeyCode.Tab))
{
TargetEnemy();
}
}

}

List uses a Type so you need to declare what type of List it is using:

public List<ObjectType> targets;

then in your start function

void Start()
{
    targets = new List<ObjectType>();
}

I dont know if im missing a using but it says it couldnt find it so it still has a mistake.
my using are
Unityengine
System.collections
and system.collections.generic.

even though i have these it still appears as if it cant find it