Coal is delivered to a power station by trains. The table below shows quantities linked to how the power station operates. Power station output $P$ (W) Number of trains per day $N$ Mass of coal on one train $M$ (kg) Energy from $1\text{ kg}$ of coal $J$ (J) Number of seconds in one day $S$ Which expression shows the efficiency of the power station?
- A$\frac{PS}{NMJ}$
- B$\frac{PSN}{MJ}$
- C$\frac{NMJ}{PS}$
- D$\frac{NM}{PSJ}$