Which of the below 2 cases can yield more fuel efficiency and why ?

1. car goin down hill in its top gear(say 5th), without using accelerator


2. the same car goin down hill in neutral gear, n the engine is running in idel


REMEMBER IN EITHER OF CASES ACCELERATOR IS NOT USED N THE ENGINE IS RUNNINGWhich of the below 2 cases can yield more fuel efficiency and why ?
In many modern car engines there's a fuel cut-off valve. In that case, the 1st scenario burns less fuel and contributes to the overall fuel economy.


The 2nd sceenario (coasting, especially downhill) is UNSAFE AT ANY SPEED; it should be avoided regardless of fuel economy considerations.Which of the below 2 cases can yield more fuel efficiency and why ?
2 but don't forget is dangerous to keep neutral while your vehicle in speed, because it will take more time to get to stop,


when the car is in gear it stops much faster then it would be in neutral.
The second case is more fuel efficient as the engine is idle at that time.. N hence there is no consumption of petrol or diesel..