Respuesta :
E, 63% of the value. I forget the rationale behind it but I learnt that in engineering. 90% confident for that answer.
The time constant is how long will the current decrease by 1/e. The numerical value of this is approximately equal to 0.37. Since we are looking at the decrease which is equal to 1 less than this value, the answer would be 0.63. Thus, the answer to this item is letter E.