Change the voice: The pilot landed the plane safely.

The plane was to be landed safely by the pilot.

The plane had been landed safely by the pilot.

The plane was landed safely by the pilot.

None of these

The original sentence is in simple past tense ("landed"), so the passive form also uses simple past: "was landed."

The object "the plane" becomes the subject in passive voice, followed by "was landed" and agent "by the pilot."