Correct option is (b) Spherical flow
Easiest explanation: The discharge of spherical flow qs is given by, qs/q =2.3(r/b) log10 1000
Let r =8cm =0.08 m
R/r =1000; b=16 m
qS/q =2.3(0.08/16) log10 1000
qS/q = 1/30
This shows that the spherical flow is much less efficient than the radial flow.