Hello there! Your answer would be: B. 3/4!
To solve this equation, you need to simplify the other fractions to start:
12/24 = 1/2
3/4 = 3/4
15/24 = 5/8
4/12 = 1/3
Looking at our options, we can straight away eliminate A and D. This is because 5/8 is greater then 4/8 (and 4/8 = 1/2), and 1/3 and 1/2 are both equal to and below 1/2.
Now, we have 5/8 and 3/4. Since the question is asking which is greater, we can eliminate 5/8, since it has the same value.
Now we have 3/4 left, which is your correct answer, but if you wanted to check it you could always multiply the numerator and denominator by 2/2. you get 6/8, which is in fact greater than 5/8.
Hope this helps, have a great day!