A. Original cross-section used for longitudinal control lines
B. Auxiliary lines
C. Conic shape with circle only
D. Elliptic contour only
I have been asked this question by my school teacher while I was bunking the class.
This intriguing question comes from Configuration Layout in portion Configuration Layout and Loft of Aircraft Design
The explanation is: Control stations are original cross section which are used to develop longitudinal lines. Control stations are also known as control cross- section. Control stations can be any type of conic curve. It can be circular, elliptic or any c/s as per our requirement.