Answer:
Can't decide, Can't decide, and mixture.
Hopefully this is right. Technically you also can't decide on C but the chances of it being a pure substance are very low.
Step-by-step explanation:
Technically, you can't decide on any of them since you have no idea of the actual compositions. Even if the ratio of the elements in grams are the same, there is no guarantee that the elements are chemically combined. For example, if you are given the info that a box contains 1 gram of hydrogen and 8 grams of oxygen, it could contain 9 grams of water, or 1 gram of hydrogen gas and 8 grams of oxygen gas. Knowing that water contains 1 gram of hydrogen and 8 grams of oxygen per 9 grams of oxygen doesn't help you determine if a container with 2 grams of hydrogen and 8 grams of oxygen has hydrogen peroxide or just a mix of the two gasses.
For A, it could be a pure substance since the ratio of E1 to E2 is twice the ratio of E1 to E2 in substance X. You can't really decide though
For B, it could be a pure substance since the ratio of E1 to E2 is four times the ratio of E1 to E2 in substance X. You can't really decide though
For C, It is very likely to be a mixture, since the ratio of E1 to E2 in substance C is 2.7 times that of the ratio of E1 to E2 in substance X