The correct answer is a , i hope this helps out
Volume of cone= 1/3 πr²*h
15²=10²+h²
h²=15²-10²=125
h=√125
Volume of cone= 1/3 *π*100*√125=π/3*(100*5√5)=500π√5/3
Volume of sphere=4/3*π*r³=4/3*π*1000=4000π/3
Volume of half sphere=(4000π/3)/2=2000π/3
All Volume=500π√5/3+2000π/3
