Why Don't Short-Period Comets Have Randomly Oriented Orbits

Multiple Choice

Why don't short-period comets have randomly oriented orbits?

A) Their orbits have been altered by encounters with planets.
B) Their orbits are altered by the Sun's gravitational pull.
C) Their orbits have been altered by impacts from asteroids.
D) Their orbits have been altered by the Lagrange points of Jupiter.
E) Their orbits have been altered by solar wind particles from a CME.