Which of the following area true?
1. A time-varying electric field will produce a magnetic field.
2. A time-varying magnetic field will produce an electric field.
3. Electric and magnetic fields can be treated independently only if they vary in time.
4. Time-varying electric and magnetic fields can propagate through space only if there is no matter in their path.

1. A time-varying electric field will produce a magnetic field.

2. A time-varying magnetic field will produce an electric field.

Explanation:

According to Maxwell a time-varying electric field will produce a magnetic field. Time varying electric field produces current (displacement current), therefore it produces a magnetic field.

According to Faraday,  a time-varying magnetic field will produce an electric field because an electromagnetic field is induced in a conductor moving in a magnetic field.

Electric and magnetic fields can only be treated independently if they do not vary in time that is they are static.

Time-varying electric and magnetic fields can propagate through space even if there is no matter in their path.