Select the word segment that substitutes (replaces) the bracketed word segment correctly and completes the sentence meaningfully. Select the option 'no correction required' if the sentence is correct as given.
(Everyone carefully and methodically were trying to) solve the problem given by the boot camp instructor.

A

Everyone had carefully and methodically trying to

B

Everyone were carefully and methodically trying to

C

Everyone was carefully and methodically trying to

D

No correction required