Mary Jane

The premise: companies get all from the only storage tank which is always refilled with the same quality of gasoline Conclusion: Different brand and prices, but identical in (same) quality B make a lot more sense. haha IF I negated B: When tankers make gasoline delivery at Haibei's seaport, the storage tank at H not always receives the same quality of gasoline as that in the preceding delivery. It's invalidated. However, after I saw price may different because of differential cost of achieving same quality before sale. Thank you.

I also chose B, but D is the correct answer.

I was confused a lot before I read this explanation. thank you. Mary Jane