I believe the answer would be J. whenever the open part of the sign is towards a number or value, that means it is greater than the other number on the other side. For example 5 is less than 6 so 5 < 6. whenever the sign in between and has a line underneath it, it means it can also be equal to the number. therefore d is the amount per day and you pay that much for 8 days, so you get 8d. Now we know you can spend $3000, but no more. so you would use this sign < with a line drawn underneath it. now you would have 8d <(with a line underneath) 3000. this means that I'd must be equal to $3000 or less than $3000.
its kind of a difficult concept to learn but once you get it, it is very simple.