Final answer:
The maximum allowable prestress force at release primarily depends on the beam cross-sectional area.
Step-by-step explanation:
The maximum allowable prestress force at release primarily depends on the beam cross-sectional area.
When determining the maximum allowable prestress force, the factor that mainly influences it is the beam cross-sectional area. A larger cross-sectional area can withstand a greater amount of prestress force before experiencing failure.
Therefore, option D) Beam cross-sectional area is the correct answer.