South Carolina's primaries end Tuesday with only two statewide runoffs, one for each party. Republicans will choose their candidate for the open Education Superintendent office, while Democrats choose their nominee for U.S. Senate to take on incumbent Tim Scott as he seeks a second full term. There also are six state House runoffs. Only one involves incumbents. Democratic Reps. Roger Kirby and Cezar McKnight were drawn through redistricting into the same district that stretches across three counties but is centered in Williamsburg County.