Let α, β and γ be real. Consider x+2y+z=7, x+αz=11, 2x−3y+βz=γ. List-I: (P) if β=(7α−3)/2 and γ=28; (Q) if β=(7α−3)/2 and γ≠28; (R) if β≠(7α−3)/2 where α=1 and γ≠28; (S) if β≠(7α−3)/2 where α=1 and γ=28. List-II: (1) a unique solution; (2) no solution; (3) infinitely many solutions; (4) x=11,y=−2,z=0 as a solution; (5) x=−15,y=4,z=0 as a solution. The correct option is: