Need the answer for this thanks. I got C but that is incorrect. Please show work thanks!

Step-by-step explanation:

a: Wrong. The first thing that you have to notice is that the sum goes to infinity. If you want k=4 to be the last condition, then take out the 3 dots.

b: That's the answer.

c: wrong. You get a real mess when you let set k = 0. Try it on your calculator.

1 ÷ 0 = Watch carefully as your calculator mentally melts down.

d: wrong. It's just not right. The highest power is k^2. There is no way to get k^3

$54.99

step-by-step explanation:

$54.99 includes 500 min. if she does not exceed 500 min then her bill is $54.99