In theory, the Habbendorf rotary engine could be a great racing engine

Source: McGraw Hill GMAT

In theory, the Habbendorf rotary engine could be a great racing engine, but in practice, it is not. The reason is that the available fuels do not have sufficient octane to obtain maximum performance from the engine.

The answer to which of the following questions would be most relevant to evaluating the adequacy of the explanation given above for why the Habbendorf rotary engine is not a great racing engine?

A. If the Habbendorf rotary engine were to operate at maximum performance levels, how would its performance compare to that of an engine recognized as a great racing engine?
B. At what level of octane in its fuel does the Habbendorf rotary engine achieve maximum performance?
C. What levels of speed, acceleration, and efficiency must an engine display in order to be considered a “great racing engine”?
D. Could a Habbendorf rotary engine be modified so that it is able to achieve maximum performance with the fuels currently available?
E. If a car equipped with a Habbendorf rotary engine were to race against a comparable car equipped with a great racing engine, by how much would the performance of the great racing engine surpass that of the Habbendorf rotary engine?

gmatexam439 This is what i understand from the question.

The argument runs on two grounds, viz one on the theoretical and other on the practical side.It is already mentioned in the argument that the engine is practically not so great since it has got issue with the octane number of the fuel.So there nothing much to be discussed about the practical aspects {because we already know why practically it is not a great engine} and now we are left with only one question .........."whether theoretically it is a great engine or not?". For that we need to assume our engine working under the ideal condition, that is the engine working on the fuel with ideal octane number and then compare the engine's performance with other great engine.

In theory, the Habbendorf rotary engine could be a great racing engine, but in practice, it is not. The reason is that the available fuels do not have sufficient octane to obtain maximum performance from the engine.

The answer to which of the following questions would be most relevant to evaluating the adequacy of the explanation given above for why the Habbendorf rotary engine is not a great racing engine?

A. If the Habbendorf rotary engine were to operate at maximum performance levels, how would its performance compare to that of an engine recognized as a great racing engine?

B. At what level of octane in its fuel does the Habbendorf rotary engine achieve maximum performance?

C. What levels of speed, acceleration, and efficiency must an engine display in order to be considered a “great racing engine”?

D. Could a Habbendorf rotary engine be modified so that it is able to achieve maximum performance with the fuels currently available?

E. If a car equipped with a Habbendorf rotary engine were to race against a comparable car equipped with a great racing engine, by how much would the performance of the great racing engine surpass that of the Habbendorf rotary engine?