💡 Detailed Explanation
'Samatageru' (妨げる) means to obstruct or hinder something from proceeding smoothly. It is most suitable for the context of hindering the 'progress of the plan' (計画の進行). 'Unagasu' (促す - to urge) has the opposite meaning. 'Michibiku' (導く - to guide) and 'kumitateru' (組み立てる - to assemble) do not fit the context.