“What do dogs do after they finish obedience school?”/“They get their masters.”

There is a difference between “master’s” (a degree) and “masters.” A dog riddle was posted on Twitter on April 15, 2013:
 
“Stupid joke of the day: What do dogs do after they finish obedience school? They get their masters. #stupidjokeoftheday”
 
The joke was posted on the website Pun of the Day on January 13, 2017.
 
     
Twitter
George The Giant
@GeorgeTheGiant
Stupid joke of the day: What do dogs do after they finish obedience school?
They get their masters.
#stupidjokeoftheday
10:00 AM - 15 Apr 2013
   
Twitter
dc roberts
@obscurecomix
WOOF!
What do dogs do after they finish obedience school?
They get their masters.
1:04 PM - 26 Nov 2016
       
Pun of the Day (January 13, 2017)
What do dogs do after they finish obedience school? They get their masters.
Category - Animals
Submitted by - RB - Norfolk, VA
 
Twitter
Just another Jokes
@factjokes
What do dogs do after they finish obedience school? They get their masters. Comment On This Pun!
2:15 AM - 13 Jan 2017
 
The Amazingly Lame Joke of the Day
Saturday, February 4, 2017
What do dogs do after they finish obedience school?
They get their masters.
Posted by Tim Wycislak at 9:40 AM
 
Facebook
Oldies Attic
February 4, 2017 ·
What do dogs do after they finish obedience school? They get their masters.
 
Twitter
jolly dad jokes
@dadtellsjokes
What do dogs do after they finish obedience school?
They get their masters.
5:15 PM - 26 Dec 2017