A $2$ km long pipe of $0.2$ m diameter connects two reservoirs. The difference between water levels in the reservoirs is $8$ m. The Darcy-Weisbachfriction factor of the pipe is $0.04$. Accounting for frictional, entry exit losses, the velocity in the pipe (in m/s) is

1. $0.63$
2. $0.35$
3. $2.52$
4. $1.25$