The given sentence is in active/ passive voice. Change the voice of the sentence. Select the correct option from the sentence below.She has preserved all the old letters of her dead lover.

• A. All the old letters of her dead lover have been preserved by her.
• B. All the old letters of her dead lover has been preserved by her.
• C. All the old letters have been preserved.
• D. The letters of her old lover have been preserved.