Consider a system with input $x(t)$ and output $y(t)$ such that
\[y(t)=t \;x(t) .\]
Consider the following statements:
- The system is linear.
- The system is time-invariant.
- The system is causal.
Then which of the following is $\text{TRUE?}$
- Only statement $1$ is correct.
- Only statement $2$ is correct.
- Only statement $3$ is correct.
- Only statements $1$ and $3$ are correct.
- All three statements $1, 2,$ and $3$ are correct.