A $1.0 \; \mathrm{kHz}$ signal is flat-top sampled at the rate of $1800$ samples sec and the samples are applied to an ideal rectangular $\text{LPF}$ with cat-off frequency of $1100 \mathrm{~Hz}$, then the output of the filter contains.
- only $800 \mathrm{~Hz}$ component
- $800 \mathrm{~Hz}$ and $900 \mathrm{~Hz}$ components
- $800 \mathrm{~Hz}$ and $1000 \mathrm{~Hz}$ components
- $800 \mathrm{~Hz}, 900$ and $1000 \mathrm{~Hz}$ components