Ratio of milk to flour is 3:6 or 1:2=1/2
Ratio of sugar to milk is 2:3=2/3
Ratio of oil to sugar is 1:2=1/2
Ratio of sugar to flour is 1:3=1/3
Which is the smallest fraction? multiply each fraction by 6: 3, 4, 3, 2. The smallest number is 2 which comes from 1/3, the ratio of sugar to flour. Another way to do it is to turn the fractions upside down and pick the largest:
2, 3/2=1 1/2, 2 and 3. The largest is 3 which is the ratio of flour to sugar, answer D.