Laugh Out Loud (Good people)

Mael was having problems getting good people to help him. He visited his counterpart in Penang, Yusof. Yusof told him, "To get good people, you must test them before you employ them."
"How?" Mael asked.
"Just ask them a simple question, and if they can answer, then they will be alright."
Just then, Sani, Yusof's deputy walked past. Yusof told Mael, "Let me show you."
Yusof asked his deputy: "Sani, who is your son's father?"
Sani answered: "Me, of course."
 Mael was impressed. When he went back to Kuala Lumpur, he tried this test on his deputy Ling, "Ling, tell me, who is your son's father?"
Ling was puzzled. He quickly tried a delaying tactic,
"Boss, I am  busy now. I will tell you after lunch."
Ling went out and met Ah Ben the cleaner. He asked,
"Ah Ben, who is your son's father?"
Ah Ben answered: "Aiyah, so easy. Me, of course."
Ling happily went back to Mael, "Hey boss. What was the question again?"
Mael repeated, Who is your son's father?"
"Simple. It is Ah Ben, of course."
Mael tore his hair in disgust. He shouted, "No! You stupid fool. It's Sani!"