Explanation:

- Section 9 of the Code of Civil Procedure says civil courts can try all suits of a civil nature unless their jurisdiction is either expressly or impliedly barred.

- Option 1: Civil courts have jurisdiction to try all suits of a civil nature.

- Option 2: They cannot try suits where their jurisdiction is expressly barred (clearly stated by law).

- Option 3: They cannot try suits where their jurisdiction is impliedly barred (not directly stated, but implied by law).

- Option 4: "All of these" combines the above points, capturing the full scope of Section 9.

Option: 4 - All of these is correct.