She replaces the lower tie bar of his car to increase the chassis rigidity by bracing the left and right lower-control-arm sheet metal mounting points

She replaces the lower tie bar of his car to increase the chassis rigidity by bracing the left and right lower-control-arm sheet metal mounting points. The lower tie bar is designed to carry a tension force of 450 KN and bolted between paired supports at A and B. The bar will be fabricated from 26 mm thick plates. For the grade of steel to be used, the maximum allowable stresses are  = 160 MPa, τ = 106 MPa, and b = 489 MPa.

a. What should be the design diameter (mm) of the bolt? Roundup/down your answer to the nearest acceptable design diameter in whole number.
b. What should be the design dimension (mm) at each end of the bar?
c. What should be the design dimension (mm) of the bar? Roundup/down your answer to the nearest acceptable design dimension in whole number.