Consider the following properties attributed to state model of a system.

1. State model is unique.

2. State model can be derived from the system transfer function.

3. State model can be derived for time variant systems.

Of these statements
(a) 1, 2 and 3 are correct
(b) 1 and 2 are correct
(c) 2 and 3 are correct
(d) 1 and 3 are correct.