Which relation is a function?

A.
{(1, 2); (2, 3); (3, 4); (2, 5)}

B.
{(1, 2); (2, 2); (3, 2); (4, 2)}

C.
{(1, 2); (2, 3); (3, 4); (1, 5)}

D.
{(1, 2); (1, 3); (1, 4); (1, 5)}

Question

Which relation is a function?
  
 
 

 
 

  

  A. 
  {(1, 2); (2, 3); (3, 4); (2, 5)}   
   

 
 

  

  B. 
  {(1, 2); (2, 2); (3, 2); (4, 2)}   
   

 
 

  

  C. 
  {(1, 2); (2, 3); (3, 4); (1, 5)}   
   

 
 

  

  D. 
  {(1, 2); (1, 3); (1, 4); (1, 5)}

anonymous · Answer

B? @zzr0ck3r

zzr0ck3r · Answer

x value must NOT map to more than one y value

zzr0ck3r · Answer

so if the set contains two elements that share a x value it is NOT function

zzr0ck3r · Answer

so which one is a function?

zzr0ck3r · Answer

oh sorry I didnt notice you already said B

$\huge CORRECT$

zzr0ck3r · Answer

all that studying is paying off:) nice work.

anonymous · Answer

sorry, my computer had a glitch. & thank you so much :)