Answer:
further tightening is required.
Step-by-step explanation:
The beat created / sec = difference of frequencies
Initial beat heard = 2
so difference of frequencies = 2
after tightening beat heard = 1
difference of frequencies decreases because frequency of tuning fork was higher than piano sound.
on further tightening difference decreases because tightening increases the frequency of piano hence further tightening is required for resonance.