Answer:
A = {MOPN, MPON, PMON, POMN}
Step-by-step explanation:
Everyone has already agreed that Naim would be the last skater, so we have to make sure that the result has 'N' in each last place. As we can see, they all have this.
Now, we also have to make sure Oliver <u>not</u> first, because although they're trying to decide, the problem asks for the <u>complement</u> in which "Oliver is the first skater in the race."
A complement is all the values that are NOT in the set, so it cannot be A = {OPMN, OMPN) or A = {MOPN,MPON, OPMN, POMN), because they both have at least one case where 'O' is first.
A complement is ALL other values of the set, so it cannot be A = {MOPN, PMON}, because that set only shows two possible values.
Therefore, A = {MOPN, MPON, PMON, POMN} is your answer.