meaning of "Went about their business"

[Dina]

Test No. incompl/inter-52 "Business Expressions (1)", question 9

When the bomb went off, most of the injured were just ordinary people going ......... their business.

(a) about
(b) along
(c) across
(d) through

Test No. incompl/inter-52 "Business Expressions (1)", answer 9

When the bomb went off, most of the injured were just ordinary people going about their business.

Correct answer: (a) about

Your answer was: incorrect
When the bomb went off, most of the injured were just ordinary people going across their business.
_________________________

Hello,

could you explain, what is the meaning of went going about their business

Thanks
Dina

[Torsten]

If you go about your business, you tend to your business, you tackle the tasks you have to carry out.

TOEFL listening lectures: An organism that generates internal heat is called what?