I think the correct answer is C
The examples of complex sentences are :
<em></em>
<em>Before you eat the sandwich, please cut it in half.
</em>
<em>
</em>
<em>When we are ready to leave, we will send you a text message.
</em>
<em>
</em>
<em>If she starts to get warm, Janna will turn on the air conditioner.</em>
<em />
They despise him and decide to leave him and never talk to him again
