Which relation represents a function?

a. (0,0) / ( 2,3) / ( 2,5) / ( 6,6)
b. (3,5 ) / (8,4) / (10,11) / (10,6)
c. (-2,2) / (0,2) / ( 7,2) / (11,2)
d. (13,2) / (13,3) / (13,4) / (13,5)

James is playing his favorite game at the arcade. after playing the game 3 times, he has 8 tokens remaining. he initially had 20 tokens, and the game costs the same number of tokens each time. the number t of tokens james has is a function of g, the number of games he plays. write the function’s formula? t=

James is playing his favorite game at the arcade. after playing the game 33 times, he has 88 tokens remaining. he initially had 2020 tokens, and the game costs the same number of tokens each time. the number tt of tokens james has is a function of gg, the number of games he plays

I’m confused on how to work the pie charts