i think the answer is C but don't take my word for it
This will be classified as light on the API scale due to the large percentage of lighter fractions such as paraffins and naphthenes.
So, you need to have same ammount of atoms on the left and on the right side of the equation. You need to count the ammount of attoms of every substance on the left, and make sure that on the right side the ammount is same. For example in the 1st one it’s 6Sn+2P4=2Sn3P4, so that you have 6atoms of Sn on the left and 6 atoms of Sn on the right, same with the P
Is there any more info lol
But from thinking I got A=DH^2*BC