The Planet Neptune Was Discovered by Means Of

Multiple Choice

The planet Neptune was discovered by means of:

A) careful observations of its motion by one astronomer in England (done over most of his lifetime)
B) observations of its motion performed over many years by astronomers all over the globe
C) radio observations of its large magnetic field
D) mathematical calculations of how it was perturbing the motion of a neighbor planet
E) discrepancies in the horoscopes of famous actors and actresses; errors in the horoscopes showed astrologers that there must be another cosmic influence on their love lives