在RC串联电路中,电流的表达式为( )<br>·<img src="/lqwvjeImg/eb/eb35716c02b04971c0ff91d20ae45087.png"style="width:84px;height:54px;"><br>·<img src="/lqwvjeImg/c0/c0c2d5100b40cb45679344378f2617d6.png"style="width:84px;height:53px;"><br>·<img src="/lqwvjeImg/66/663d1a06b74e246bf7b3a13f27609ee3.png"style="width:100px;height:50px;"><br>·<img src="/lqwvjeImg/79/7964702e83900b6c4833de0598c42f25.png"style="width:84px;height:56px;">