What evidence do historians use to show that the maya had advanced knowledge of astronomy

The choices can be found elsewhere and as follows:

a. Huge temples aligned to  four cardinal directions 
b. The maya developed a 365 day solar calendar
c. The maya had identified all the planets in the solar system   
d. Maya priests invented concept of zero 

I think the correct answer is option B. The evidence that historians use to show that the maya had advanced knowledge of astronomy is that the maya developed a 365 day solar calendar.