The answer is D
Hope this helps!
If you want a detailed step by step ask me
10:4 is the ratio you're looking for.
The slope of the line below shown is -4
So :

?
First, you want to bring everything together on the top of the fraction.
12=24/2 so you can have

Add like terms -- 12 +24 = 36

Now we are at

Which is the lowest possible simplified version while remaining at exact value.
Feel free to check my math! I kinda did this off the top of my head.