Answer :
Final answer:
To stack rails in a single hydro hoistway with a rise of 48', you will need 6 rails. so, the correct option is:(d) 6 rails
Explanation:
To find the number of rails needed when stacking in a single hydro hoistway with a rise of 48', you can use the formula:
Number of rails = Total rise / Rise per rail
Given the rise is 48' and each rail has a rise of 8', you will need 6 rails to achieve the 48' rise.