4. 如【圖 3】所示之電路,若 I 2 = 0A ,則 R 與 I1 分別為何? (A)R = 6Ω,I1 = 5A(B) R = 6Ω,I1 = 3A(C) R = 8Ω,I1 = 3A(D) R = 8Ω,I1 = 5A