A $10$ $^1/_2$ digit Counter-timer is set in the 'frequency mode' of operation (with $T_{s}=1 s$). For a specific input, the reading obtained is $1000$. Without disconnecting this input, the Counter-timer is changed to operate in the 'Period mode' and the range selected is microseconds ($\mu s$, with $f_{s} = 1\text{ MHz}$). The counter will then display
- $0$
- $10$
- $100$
- $1000$