The correct answer is D) The discharge is slow due to the size of the cargo and all the cranes working together. This is correct because when performing a quad lift using tandem working arrangement of pedestal cranes, the cargo discharge process is inherently slow due to the coordination required between the multiple cranes to handle the large, heavy cargo. The size and weight of the cargo necessitates the use of all the cranes working in tandem, which makes the discharge a slower process compared to handling smaller cargo with fewer cranes. The other options are incorrect because: A) Shoreside assistance is not required for the tandem crane operation, B) Pendulation is not a necessary factor in the cargo discharge, and C) The cargo can be discharged at anchor using the tandem crane arrangement.