D. Each statement alone is sufficient
Question stem tells us:
The previous weights of the liquid are- a, b, c
I am assuming total weight to be 30 (by looking at the question and statements, I understood two things: 1. As we have to get the ratio of a with total quantity, the absolute total quantity does not matter 2. I assume total weight to be something that can be easily divided by 5, 6 and 3)
After increasing the weights become- 4a/3, b, c and total weight is 30 + a/3
Now, we have to find out the ratio of previous base liquid to total weight, which is: a/30
Statement 1: b/30 is 1/5 and b/(30+a/3) is 1/6
So, we can find out b and then we can find out a, which will give us our previous ratio for a/30
Statement 2: New ratio for base liquid/total is given: a/(30+a/3) = 2/3
We can get a from this and hence the previous ratio
So, each statement alone can give us the answer