What is the angle between vernal equinox and to the ascending node called?

A)
Semi-major axis
B)
Argument of periapsis
C)
Longitude of ascending node
D)
Right ascension at epoch

Correct Answer :   Longitude of ascending node


Explanation : Longitude of ascending node is known as the angle in the fundamental plane between the vernal equinox and the point where satellite crosses through the fundamental plane in northerly direction (ascending node. That is why it is also known as right ascension of ascending node. It is measured counter clockwise when it is viewed from the north side of the fundamental plane.