Object P travels backwards and forwards along a straight line at a constant speed of $5\,\text{m s}^{-1}$. Object Q travels vertically downwards at a constant speed of $5\,\text{m s}^{-1}$. Object R travels in a circle at a constant speed of $5\,\text{m s}^{-1}$. Which objects are moving with uniform velocity?
- AP only
- BQ only
- CR only
- DQ and R