若集合D1={0,1,2}、集合D2={a,b,c}、集合D3={a,c},則D1×D2×D3應(yīng)為(1)元的集合,其結(jié)果集的元組個(gè)數(shù)為(2)。若,則結(jié)果集的元組個(gè)數(shù)為(3)。(1)A.3B.6C.8D.9(2)A.6B.9C.12D.18(3)A.2B.3C.6D.9