Quantum mechanics describes the behavior of particles at the smallest scales ______ classical physics breaks down entirely at this level, revealing a strange and counterintuitive reality.
Which choice completes the text so that it conforms to the conventions of Standard English?
- A
(empty)
- B
:
- Ccheck_circle
;
- D
, but,
Explanation
Both clauses are independent and equally weighted, with the second describing a related phenomenon. A semicolon best joins them. A colon would suggest the second clause defines or explains the first more directly; " " is a run-on; ", but," is over-punctuated.