|Question 18Verbal

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The Southern Delta Aquariid meteor shower has a zenithal hourly rate (ZHR) of 25, meaning that at the shower's peak, 25 meteors per hour could potentially be seen by a hypothetical observer. A calculation that assumes ideal viewing conditions,       
Which choice completes the text so that it conforms to the conventions of Standard English?
an actual viewer's observed number of meteors in an hour and the ZHR may differ considerably.
A
the number of meteors an actual viewer observes in an hour may differ considerably from the ZHR.
B
there may be a considerable difference between the number of meteors an actual viewer observes in an hour and the ZHR.
C
the ZHR may differ considerably from the number of meteors an actual viewer observes in an hour.
D