Both 7 and 8 appear, at first sight, to be true...
If there is no change in velocity then there is no acceleration.
If there is no change in velocity than the velocity is constant (even if it is zero.)
HOWEVER that "assume the quantities are instantaneous" makes it a whole different ballgame!
Just because an object has the same INSTANTANEOUS velocity at the start and end of an interval tells us nothing about what happened DURING the interval.
Therefore, the correct answer is 1 because the object could have sped up, slowed down or changed direction and then gone back to it's original speed and direction during the interval.
"A short time interval" is absolutely meaningless!
Are your engineering units of time: seconds, hours, days, months, years, decades, centuries or what?
0.01 centuries is an entire year!
"Short" is an arbitrary and relative concept that is meaningless without further definition.
e.g.; Let's define our short time interval as 2 seconds.
If I am holding a brick in my hand 1 meter above the ground and start my stopwatch; the initial velocity is zero.
At the end of 2 seconds the brick is sitting on the ground with a final velocity of zero.
(I released the brick half a second after I started the stopwatch.)
I know that the initial instantaneous velocity of the brick at the start of the interval was zero and that the instantaneous velocity of the brick at the end of the interval was also zero.