State the Problem  
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The figure shows a L shaped rigid bar B C D. Segment B C has a height of 0.4 meters and segment C D has a height of 0.6 meters. The bar is pinned at C and supported at B by a 2 meter long horizontal rod A B with a diameter of 25 millimeters. The rod is pinned to a bracket on a wall at the point A. A 50 kilo newton load acts at the midpoint between C and D and a 15 kilo newton load acts at point D.

A pin at C and a round aluminum rod at B support the rigid bar BCD. If the allowable pin shear stress is 50 MPa, what is the minimum diameter required for the pin at C?