Question - Falsifiability

This question provided a text on a theory of science - that all scientific theories are scientific theories because they are falsifiable. I do not recall enough about the prompt on this question to locate or recreate it, so I will instead direct you to an article by Karl Popper, a philosopher of science, entitled "Science as Falsification" and originally published in 1963. Please keep in mind that this piece is significantly longer than a standard GAMSAT prompt.

Questions:

A scientific theory must be:
A. Broad and sweeping
B. Unspecific and topical
C. Creative and innovative
D. Specific and testable

Considering the following three theories:
I. The earth is flat
II. The sun orbits the earth
III. The earth orbits the sun

Which of these is a scientific theory?
A. I only
B. I and III only
C. II and III only
D. All of I, II and III