Answer:
The 4th option, 10g + 24 = t
Explanation:
It costs 24 dollars per month no matter what.
$10 * the amount of GB you want
Add those two values to get the total cost per month.
In this case you want 5 GB, so substitute the g in the equation for 5. You will get:
10 * 5 +24 = t
50 + 24 = t
74 = t
So it costs 74 dollars per month to get 5 GB.