Given a collection of names, there may be a name 10 chars

Question

given a collection of names, there may be a name that is 10 characters or longer, return this name or null if none found, throw and exception if there is more than 1

 

public static string GetLongestName(IEnumerable<string> names)

{

 

//code

}

 

I am new to linq and c# . please help.