Suffolk Construction was selected on Dec. 16 as construction manager for General Electric Co.’s new $200-million global headquarters, a planned 12-story, 295,000-sq-ft building on a 2.5-acre campus in Boston’s Fort Point area. In phase one, Suffolk and project architect Gensler will complete the design and develop project sequencing and logistics. An industry source close to the project competition says other bidders were Skanska USA, Consigli Building Group Inc., Shawmut Design and Construction, and a Gilbane Co.-Sciame Construction team. A contractor spokesman declined to disclose the cost of Suffolk’s contract.