For the R-L circuit shown in the figure, the input voltage vi(t) = U(t). The current i(t) is

• A. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/141-974-2.png">
• B. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/141-974-3.png">
• C. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/141-974-4.png">
• D. <img src="/_files/images/electronics-and-communication-engineering/networks-analysis-and-synthesis/141-974-5.png">