I believe the answer would be , it may change from one element to another. I’m saying this because during nuclear transmutation is when a subatomic particle fired at the nucleus of an atom changes into a heavier element , to break the nucleus apart into two nuclei and energy.
For the First answer, It would be "A"
The for the next one the answer is "C"
I hope this helps. :)
Speed = (distance covered) / (time to cover the distance)
= ( 8.45 km) / (0.65 hr)
= (8.45 / 0.65) km/hr
= 13 km/hr