&lt;?php        define&#40;&quot;GREETING1&quot;,&quot;Hello you! How are you today?&quot;&#41;;        define&#40;&quot;GREETING2&quot;,&quot;Hello you! How are you today?&quot;&#41;;        define&#40;&quot;GREETING3&quot;,&quot;Hello you! How are you today?&quot;&#41;;        echo defined&#40;&quot;GREETING&quot;&#41;;     ?&gt;
A. 1
B. 0
C. 3
D. 4
Answer:A
&lt;?php        define&#40;&quot;GREETING1&quot;,&quot;Hello you! How are you today?&quot;&#41;;        define&#40;&quot;GREETING2&quot;,&quot;Hello you! How are you today?&quot;&#41;;        define&#40;&quot;GREETING3&quot;,&quot;Hello you! How are you today?&quot;&#41;;        echo defined&#40;&quot;GREETING&quot;&#41;;     ?&gt;
A. 1 B. 0 C. 3 D. 4
Explanation: The defined() function checks whether a constant exists.