In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: The story encompasses around nine characters portraying nine variants of emotion and an outdated dam.The story starts with Vinay, who is a mariner and works in ships. One day he visits his native place, somewhere in Kerala, with his son Sam to meet his father Shankaran. Shankaran is a village doctor or 'Vaidyan' and is also a master in astrology and the ancient sciences. Sam is a Diabetic and Vinay wanted to have him treated by his grandfather. Another story line is that of the orphan Meera, who has been staying with Shankaran since her childhood, treated as his own daughter and who helps him treat various patients. Vinay and Meera share a special bond and love each other. But when Shankaran studied their horoscopes, he learned that whenever they express their love towards each other, something terrible would happen. Learning this Meera sacrificed her love, and thus Vinay married Sandra who is a TV journalist. Now after a long time when Vinay returns home with his son, his special bond with Meera develops again with Meera reciprocating the feeling as well. On a parallel track, a corrupt Mayor - Durai (Ashish Vidyarthi)- is fighting an issue of an old dam in his area. Towards the end a leak is discovered inside the dam, and when a heavy storm and rains hit on the same day, a high alert is declared.
Who is the Vaidyan's son?