|Question 18Verbal

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Text
The small celestial body known as 2060 Chiron is expected to have a relatively short lifetime in the outer solar system. Within just a few million years, 2060 Chiron is likely to migrate into the inner solar system or be destroyed, according to        trajectory.
Which choice completes the text so that it conforms to the conventions of Standard English?
astronomers modeling of the object's
A
astronomers' modeling of the object's
B
astronomers modeling of the objects
C
astronomer's modeling of the object's
D