The answer is A. Heat flows from high to low. For example, when you put an ice cube in a hot drink, the heat from the drink goes to the ice cube, and that is why it melts.
(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.
Recall that

We have
, so that

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.
(c) The ball's average velocity is 0. Average velocity is given by
, and we know that
.
(d) The position of the ball
at time
is given by

Take the starting position to be the origin,
. Then after 6 seconds,

so the ball is 42 m away from where it started.
We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

Since the velocity is positive, the ball is still moving up the incline.
Balance:
a book resting on a table
a car driving at 10 miles per hour in constant velocity
a cat sitting on a chair
a bulb that attach to the ceiling
your grandma sleeping on a bed
Unbalance:
your brother sprinting across the kitchen
a ball rolling at 5 m/s^2
your mom trying to run at 2 m/s^2 to spank you
you dropping your coffee mug on a floor
a cat jumping out of your bed
a tear from your eye falling through the floor
Hope this helps
Sawmills rely on electricity to run the cutting blade.