What advantages do buying call options on futures have over a long positions on futures?

What advantages do buying call options on futures have over long positions on futures? a. options are zero-sum games whereas futures on options are not zero-sum games b. the amount that you can potentially lose on the futures position is greater than the amount that you can potentially lose on the option position c. marking to market exists with the options position, but not with the futures position d. both a and b above are correct e. both b and c above are correct