Average waiting time $($WT$)$ for a truck at a vendor$$s shipping dock increased by about $20\%$ when capacity utilization of the dock went up from $40\%$ to $60\%.$

What may be the likely change in avg. waiting time if a surge in demand makes the vendor$$s shipping dock capacity utilization go up from $60\%$ to $80\%?$

Question $19$ options:

The avg. WT would likely go up by more than $20\%$

The avg. WT would likely go up by another $20\%$

The avg. WT would remain unchanged.

The avg. WT would generally go down, and not up