The angle between magnetic north and the north to which a compass needle points is known as magnetic declination. select the best answer from the choices provided t f

From among the choices provided, the better choice is the upper-case letter 'T '.  That symbol can conveniently be used to represent the words "true" or "truth", which is exactly the reason that it is the better choice for a response, since the complicated statement at the beginning of the question is completely true in its every detail, nuance, jot and tittle.  

d) physical means can be used to separate the components of air.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.