The first step is taking the Amount given to her mother away from the total. So subtracting 25-c. Then this need to be split amongst 4 friends or divided by 4. The last option is correct because it uses PEMDAS or the order of operations correctly.
because all the other expressions are suggesting another equation they said Emma made 25 cookies and gave her mom c so that will be 25-c and then she divided it between her four friends so therefore 25-c,c=the amount she gave her mom,it is unknown so 25-c =the amount remaining after she gave her mom divided by 4