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
Sights must be made at even time increments to benefit from the tables.
C
Only certain stars are included and sights must be limited to those stars.
D
Only first magnitude stars are tabulated.
E