As a mathematician (BS, 1992) I read "into thirds" as producing 3 equal results. (When I teach it to kids, I tell them you are sharing equally among 3 friends/3 plates/3 bags...
Choice A is correct.
How would “40 divided into thirds” be written?
A. 40 ÷ 3
B. 40 ÷ 1/3
Why?