Oort Cloud Theory?

Question

The Oort cloud theory expains the existence of long-period comets.

Upon which of the following id dJan Oort base his theory?

Choose 3 of the following:

A. Long-period comets orbit outside the plane of the ecliptic.

B. Radio telescopes depect icy bodies at immense distances from the sun

C. New Long-Period comets continue to be seen

D. Orbital paths of the planets indicate that many small outer bodies exist.

E. Al comets disappear after enough passes around the sun.

Answer 1

a, c and e

Answer 2

a.b.c.

Answer 3

I go with A, B & C