3 The following sets are given: 1. S={(1, 0): 1 ER} CR 11. S = {(1, 1) 1 R} CR : 11. S = {(x1, x2): x1 + x2 = 1 and 21, 22 R} CR Choose the correct answer. a) D) I,II and III are subspaces e subspac I and II subspaces, III is not subspace I is subspace, II and III are not subspaces d) I and III are subspaces, II is not subspace