Final answer:
The well-defined collection among the given options is 'a collection of whole numbers less than 20,' as it clearly specifies the elements of the set without ambiguity.
Step-by-step explanation:
The question asks which of the following options is a well-defined collection. A well-defined collection is a set where it is possible to determine whether an element belongs to it or not, without any ambiguity.
- a. A collection of greater natural numbers: This option is not well-defined because there is no upper limit to natural numbers, and 'greater' is not specific enough.
- b. A collection of favorite English alphabet: This option is not well-defined as 'favorite' is subjective and can vary from person to person.
- c. A collection of whole numbers less than 20: This option is well-defined because it specifies a clear set with whole numbers ranging from 0 to 19.
- d. A collection of long rivers of Nepal: This option may not be well-defined without specifying what is considered 'long' for a river.
Therefore, the well-defined collection among the given options is c. A collection of whole numbers less than 20.