5.如圖(1)所示 RLC 並聯交流電路,已知= 100∠30°,R = 20Ω、XL = 10Ω、XC = 20Ω,則下列敘述何者正確? (A) 相角超前相角 30° (B)相角超前相角 90° (C) = 5∠-15° A (D) = 5∠0° A