In the situation described, where Seth has concerns about his ability to supply the artwork for the text he is writing, the most effective strategy during the planning stages of a group project would be:
B. Choose roles.
By clearly defining and assigning specific roles within the group, Seth can either be assigned a role that matches his skills or the group can decide to assign the artwork task to someone more skilled in drawing. This clarity can help prevent uncertainty about responsibilities and capabilities within the project.