电路如图所示，当t=0时开关闭合，闭合前电路已处于稳态，电流I（t）在t≥0以后的变化规律是（）<img src="/Image1/55/5554aa13b373a8940c54748ab9f23075.jpg" /><br>A:4.5-0.5<img src="/Image1/c5/c50be59f01d37865d944b5a89adc3817.jpg" />A.<br>B:B.4.5-4.5<img src="/Image1/c5/c50be59f01d37865d944b5a89adc3817.jpg" /><br>C:C.3+0.5<img src="/Image1/c5/c50be59f01d37865d944b5a89adc3817.jpg" /><br>D:D.4.5-0.5<img src="/Image1/c5/c50be59f01d37865d944b5a89adc3817.jpg" />