Please explain thoroughly and show how you derived all the equations

A circuit is constructed with three resistors and one capacitor as shown. The values for the circuit elements are: 0R1=R3=6Q 01222129 00:50uF 0V:48V The capacitor is initially uncharged. At time t = 0 the switch S is closed. What is the magnitude of the current through R1 immediately after the switch is closed? 0 (a) 4 A O (b) 1.6 A O (c) 3.2 A 0 (d) 2.67 A 0 (e) O A