This question was set by the previous examiner and is very unfair for using those terms (and the examiner was told off because of it). There is no chance of the current examiner using the terms ‘open’ and ‘settlement’.
They are terms used in newspapers when printing the price of futures. ‘Open’ the price at the start of the day; and ‘settlement’ is the price at which deals actually occurred at during the day.
So the only relevant one is ‘settlement’ and it is ‘today’s’ price of the future. (Not the price when the deal is closed, but the price today.)