public Dropdown dd;
Resolution[] res;
void Start()
{
Resolution [] resolution = Screen.resolutions;
res = resolution.Distinct().ToArray();
string[] strRes = new string[res.Length];
for (int i = 0; i < res.Length; i++)
{
strRes[i] = res[i].width.ToString() + "x" + res[i].height.ToString();
}
dd.AddOptions(strRes.ToList());
}
Screen.resolutions.Select(x => x.ResolutionName).Distinct();