A is the answer because if we want the unit rate we do
2/3÷2/3 and 15 1/5, we can turn 15 1/5 into a improper fraction first so 76/5 and we do 76/5 ÷2/3 which is equal to
76/5×3/2=114/5
114/5 simplifies into 24 4/5.
so Naomi can travel 24 4/5 gal per mile.
Hope this helps!