4/5 - A
I feel the easiest way to simplify this fraction would be to divide by 2 every time you want to simply it more. First, you would divide both the numerator & the denominator by 2. this would get you 12/15(24/2 over 30/2). After that, you wouldn't be able to divide this by two once more. So here you can look for the greatest common factor, which is the largest number both can be divided by. In this example, it would be 3, so all you do now is divide both by 3. This would leave you with 4/5(12/3 over 15/3), which can not be simplified further.