Lambda expression cannot have 'params' parameter

Func&lt;string[], string&gt; GetLongestItem = (params string[] <-:caret:->strings) =&gt;
{
    string result = string.Empty;
    foreach (string str in strings)
        if (str.Length > result.Length)
            result = str;
    return result;
};

Func<string[], string> GetLongestItem = strings =>;
{
    string result = string.Empty;
    foreach (string str in strings)
        if (str.Length > result.Length)
            result = str;
    return result;
};