Each of three boxes has a weight of $100\,\text{N}$. A man raises all the boxes together from the ground to a shelf $1.5\,\text{m}$ above the ground. He takes $2.0\,\text{s}$ to complete this. What useful power does the man output in lifting the boxes?
- A$75\,\text{W}$
- B$225\,\text{W}$
- C$300\,\text{W}$
- D$900\,\text{W}$