Convert List<String> to string C# - asp.net - sql server - : <p>I am new to this and I am asking for help to convert a string type data, I made an sql connection where I returned a name, address and phone number found in another table</p>

<p><a href="https://i.stack.imgur.com/7UVEp.png" rel="nofollow noreferrer"><code>List string eTelefono</code></a>
<a href="https://i.stack.imgur.com/VNAOq.png" rel="nofollow noreferrer"> <code>while _Reader.Read</code></a>
<a href="https://i.stack.imgur.com/z9Ud6.png" rel="nofollow noreferrer">Builder</a></p>

<p>(If you see something in spanish is beacause im from Uruguay)
This the error 
<a href="https://i.stack.imgur.com/6TxWB.png" rel="nofollow noreferrer"><code>error System.String to System.Collections.Generic.List 1 System.String</code></a></p>

<p>Does anyone know how to convert <code>List &lt;string&gt;</code> to <code>string</code>?</p>

<p>Thanks!
If you need more captures just ask</p>
