Can More Than One Planet Be Found in the Same

Multiple Choice

Can more than one planet be found in the same habitable zone around a single star?

A) No, habitable zones are too small for more than one planet.
B) No, two planet orbits would not be stable inside the same habitable zone.
C) No, habitable zones are defined on a per-planet basis.
D) Yes, in theory, but this has not yet been observed.
E) Yes, and this has been observed.