An S 12x40.8 of A36 steel in a building is supported as a simple beam having a span equal to 17ft 6in. and carries a uniform load equal to 1.60 klf, which includes the weight of the beam over the entire span. A) Compute the maximum fiber stress. B) If the compression flange of the beam is supported laterally only at the ends of the span, what will be the allowable compressive stress in the extreme fibers?