|Question 21Verbal

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As of 2017, Italy's top tax rate of 55% was lower than the country's Laffer curve peak (70%). To some economists, whether a tax cut will ultimately increase Italy's tax revenue is dependent on the country's position on the Laffer ________ a theoretical relationship between tax rates and revenues, the curve was famously sketched on a napkin by economist Arthur Laffer in 1974.
Which choice completes the text so that it conforms to the conventions of Standard English?
curve
A
curve;
B
curve, which is
C
curve,
D