Any motion that is regular and repeating is referred to as a periodic motion...
a) the greater the mass of the spring, the greater the periodic motion.
b) the lower the mass of the spring, the faster the repeating motion occurs.
c) the periodic motion will continue forces acting on the spring are unbalanced.
d) there is an equal and opposite reaction force that slows down the periodic motion.
The spring undergoes periodic motion. From Newton's first law, a body keeps moving until an unbalanced external force acts on it. So, the spring would continue to vibrate regularly and in repeated fashion. In the absence of any dampening force, the spring continues to oscillate.
Thus, option C is correct.
the maxium height is 34m/s