Explanation:

- Option 1: Young and Wilmott – Known for their studies on family and community in sociology, not specifically for writing “Assimilation”.

- Option 2: Park and Burgess – These sociologists introduced the concept of assimilation in urban sociology, but they did not write a book titled “Assimilation”.

- Option 3: Fairchild – He wrote extensively on human relations and social psychology, including the process of assimilation, but is not credited with a book titled “Assimilation”.

- Option 4: V. Punekar – He authored the well-known book “Assimilation”, which discusses the process and theories related to assimilation in sociology.