Select the correct passive form of the given sentence.
Gulliver easily pulled all the warships of the enemy after him.

Options

A. All the warships of Gulliver were easily pulled by the enemy after him
B. All the warships of the enemy were being easily pulled by Gulliver after him.
C. All the warships of the enemy had been easily pulled by Gulliver after him
D. All the warships of the enemy were easily pulled by Gulliver after him

Explanation

(a) The secret of leading a long and meaningful life is explored in this book. (Correct) (b) The secret of leading a long and meaningful life was being explored by this book. (Tense has changed) (c) The secret of leading a long and meaningful life have been explored by this book. (Tense has changed) (d) The secret of leading a long and meaningful life had been explored by this book. (Tense has changed)