Which contenttypes can we use in the sendReply api?

Which contenttypes can we use in the sendReply api?

Hello?

are there any other than plain text Content types that we can use in the sendReply api
 I'm trying to send the following content but i'm getting an invalid data type error

"<p><strong>Dit is&nbsp;<em>een</em></strong></p>

<ul>
    <li><strong><em>test</em></strong></li>
    <li><strong><em>om</em></strong></li>
</ul>

<p><strong><em>ff te&nbsp;</em></strong></p>

<p style=""text-align:center""><strong><em>checken&nbsp;</em></strong></p>

<p><strong><em>snappie</em></strong></p>

<p><strong><em><span style=""color:#2ecc71"">kleurtje erbij</span></em></strong></p>

<p><strong><em><span style=""color:#2ecc71""><samp><span class=""marker"">ziekkk</span></samp></span></em></strong></p>
"
Is there any way to achieve this?