HELP ASAP

Which innovation from the Song dynasty had the greatest impact on the expansion of global empires?
A. Accurate star charts
B. Horse stirrups
C. Better navigation tools
D. Chemistry for explosives.

I think it could be C

Question

HELP ASAP

Which innovation from the Song dynasty had the greatest impact on the expansion of global empires? 
A. Accurate star charts 
B. Horse stirrups 
C. Better navigation tools 
D. Chemistry for explosives.

I think it could be C

daddysbabygirl · Answer

Well looking at A and B it is clearly not those choices. Looking at C and D is very close. But I've taken this class so I know it is C. Can you explain why you think it is C? Or would you like me to explain it ?