Calculate the maximum force F for the I-beam with holes. Given the yield strength is 355 MPa, and the safety factor is 1.5, what is the permissible force?
a. X kN (Tension at x=5.0 m)
b. X mm⁴ (Square moment without holes)
c. X mm⁴ (Square moment with holes)
d. X kN (Tension at x=6.8 m)