The name 'TimeZone' does not exist in the current context

While trying to do a Windows 10 build I'm getting this error for TimeZone
SDK Universal 10

Code (csharp):

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2. int currentOffset = (int)TimeZone.CurrentTimeZone.GetUtcOffset( System.DateTime.Now).TotalSeconds;
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also got another one I'm not sure about
It doesn't like the JSONObject I'm passing in the agrument

Code (csharp):

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2. Assets/Politics.cs(255,39): error CS0012: The type `System.Object' is defined in an assembly that is not referenced. Consider adding a reference to assembly `System.Runtime, Version=4.0.20.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
3.  

Code (csharp):

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2.     static public void ShowLocationPicture(JSONObject planet_details_data, Image LocationPicture) {
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using TimeSpan compares DateTimes and returns the result in any time count desired

https://msdn.microsoft.com/en-us/li...?cs-save-lang=1&cs-lang=csharp#code-snippet-1