2. Given below are four sentences. While three of them are correct, one is not acceptable in formal English as it is grammatically incorrect. Spot that sentence.
A. How closely this reconstruction matches up to the original will never be known.
B. The purpose of two dials on the back of the device is still unclear, although one may indicate the year.
C. Nor is the devices purpose obvious: it may have been an astrological computer, used to speed up the casting of horoscopes, though it might just as easily have been a luxury plaything.
D. But Mr Wright is convinced his epicyclic interpretation is correct, and that the original device modelled the entire known solar system.