What is the major limitation in using the sight reduction Tables for Air Navigation Volume I (Pub.No. 249) for star sights?

A
More accuracy is needed for celestial observations on board ship than what is tabulated.
B
Only first magnitude stars are tabulated.
C
Sights must be made at even time increments to benefit from the tables.
D
Only certain stars are included, and sights must be limited to those stars.
E