The angle of dip is the angle between:
A) the vertical component of earth's magnetic field and magnetic meridian
B) the vertical component of earth's magnetic field and geographical meridian
C) earth's magnetic field direction and horizontal direction
D) the magnetic meridian and the geographic meridian

Hint: The dip angle, I is the angle that the net field vector makes concerning the flat plane and is positive for vectors underneath the plane. It is the supplement of the typical polar angle of circular directions.

Complete answer:
We know the Angle of dip is otherwise called the magnetic dip and is characterized as the angle that is made by the world's magnetic field lines with the level. We also know that; the angle of dip fluctuates from highlight point by giving the data identified with the development of the world's magnetic field. The angle of dip is supposed to be positive when the magnetic field focuses downwards. At the point when the magnetic field focuses upwards, the angle of dip is supposed to be negative.
From the above definition, we can conclude the facts that,
The angle of dip is $0{}^\circ$ when the dip needle rests evenly while the angle of dip is $90{}^\circ$ when the dip needle rests vertically.
At the point when the flat part and the vertical segment of the world's magnetic field are equivalent, the angle of dip is equivalent to $45{}^\circ$.
Therefore, we can determine that the angle of dip is the angle between earth's magnetic field direction and horizontal direction.

Hence, the correct answer is Option C.

Note: The scope of dip is from $-90{}^\circ$ (at the South Magnetic Pole) to $+90{}^\circ$ (at the North Magnetic Pole). Shape lines along which the dip estimated at the Earth's surface is equivalent are alluded to as isoclinic lines.