The diagram depicts a circuit junction where three wires, P, Q and R, are connected. The currents in P and Q are $1\,\text{A}$ and $3\,\text{A}$ respectively, in the directions indicated. How much charge passes a fixed point in wire R during a time of $5\,\text{s}$?
- A$0.4\,\text{C}$
- B$2\,\text{C}$
- C$10\,\text{C}$
- D$20\,\text{C}$