(i) The collection of all months of a year beginning with the letter J is a well-defined collection of objects because one can definitely identify a month that belongs to this collection.Hence, this collection is a set.(ii) The collection of ten most talented writers of India is not a well-defined collection because the criteria for deterring a writer's talent may vary from person to person.Hence, this collection is not a set.(iii) A team of eleven best cricket batsmen of the world is not a well-defined collection because the criteria for deterring a batsman's  talent may vary from person to person.Hence, this collection is not a set.(iv) The collection of all boys in your class is a well-defined collection because, you can definitely identify a boy who belongs to this collection.Hence, this collection is a set.(v) The collection of  all natural numbers less than 100 is a well-defined collection because one can definitely identify a number that belongs to this collection.Hence, this collection is a set.(vi) A collection of novels written by the writer Munshi Prem Chand is a well-defined collection because one can definitely identify a book that belongs to this collection.Hence, this collection is a set.(vii) The collection of all even integers is a well-defined collection because one can definitely identify an even integer that belongs to this collection.Hence, this collection is a set.(viii) The collection  of questions in this chapter is a well-defined collection because one can definitely identify a question that belongs to this chapter.Hence, this collection is a set.(ix) The collection of most dangerous animals of the world is not a well-defined collection because that criteria for detering the dangerousness of an animal can vary from animal to animal.Hence, this collection is not a set.