where we used singleton in our .net project ?explain with ex

Question

Hi frnds

 

i know about the singleton.

 

here i want to know that where we used in our application.

 

i went for the interview that time this qus asked to me so i gave the ans then they asked me where you used in your application so i  replied in master page ,my answered was wrong,

 

 

 

please clear on this.