How much ideal efficiency should practical turbine have?

1.	How much ideal efficiency should practical turbine have?
A.	10 ‚Äö√Ñ√∂‚àö√ë‚àö¬® 12%
B.	18 ‚Äö√Ñ√∂‚àö√ë‚àö¬® 25%
C.	80 ‚Äö√Ñ√∂‚àö√ë‚àö¬® 90%
D.	50 ‚Äö√Ñ√∂‚àö√ë‚àö¬® 70%
Answer» E.

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