The correct answer is: B. Flow nozzle is cheaper than venturimeter but has higher energy loss.
A venturimeter is a device used to measure the flow rate of a fluid. It consists of a converging section, a throat, and a diverging section. The fluid enters the converging section and is accelerated, causing a decrease in pressure. The fluid then passes through the throat, where the pressure is at its lowest. The fluid then enters the diverging section and is decelerated, causing an increase in pressure. The pressure difference between the inlet and outlet of the venturimeter is proportional to the square of the flow rate.
A flow nozzle is a type of venturimeter that has a very short throat. This results in a higher pressure drop across the flow nozzle than across a venturimeter with a longer throat. The higher pressure drop results in a higher energy loss for the flow nozzle.
The other options are all correct. The coefficient of contraction of a venturimeter is unity, which means that the area of the throat is equal to the area of the vena contracta. The discharge is independent of the orientation of the venturimeter, whether it is horizontal, vertical, or inclined.