Sentence Correction

Whereas a ramjet generally cannot achieve high speeds without the initial assistance of a rocket, high speeds can be attained by scramjets, or supersonic combustion ramjets, in that they reduce airflow compression at the entrance of the engine and letting air pass through at supersonic speeds.

A) high speeds can be attained by scramjets, or supersonic combustion ramjets, in that they reduce
B) that high speeds can be attained by scramjets, or supersonic combustion ramjets, is a result of their reducing
C) the ability of scramjets, or supersonic combustion ramjets, to achieve high speeds is because they reduce
D) scramjets, or supersonic combustion ramjets, have the ability of attaining high speeds when reducing
E) scramjets, or supersonic combustion ramjets, can attain high speeds by reducing

E