&lt;?phpfunction sayHello&#40;&#41;&#123;   echo &quot;HelloWorld&lt;br /&gt;&quot;;&#125;$function_holder = &quot;sayHello&quot;;$function_holder&#40;&#41;;?&gt;
A. No Output
B. Error
C. sayHello
D. HelloWorld
Answer:A
&lt;?phpfunction sayHello&#40;&#41;&#123;   echo &quot;HelloWorld&lt;br /&gt;&quot;;&#125;$function_holder = &quot;sayHello&quot;;$function_holder&#40;&#41;;?&gt;
A. No Output B. Error C. sayHello D. HelloWorld
Explanation: It is possible to assign function names as strings to variables and then treat these variables exactly as you would the function name itself.