The microscope was invented in the late 1500s ______ it took decades before scientists fully grasped the implications of microbial life.
Which choice completes the text so that it conforms to the conventions of Standard English?
- A
but
- Bcheck_circle
, but
- C
; but,
- D
, but,
Explanation
Comma plus FANBOYS "but" properly joins two contrasting independent clauses. " but" is a run-on; the others are over-punctuated.