She will open the door. (passive)

The correct answer is - খ) The door will be opened by her.

• Tense: Future Indefinite (will + base verb).
- Passive Voice Structure (Future Indefinite এর জন্য):
- Object + will be + past participle (V3) + by + subject.
- Active Sentence: She will open the door.
- Passive sentence: The door will be opened by her.

Other options:
ক) The door is opened by her. - Present Simple (Passive).
খ) The door was opened by her. - Past Simple (Passive).
ঘ) The door has been opened by her. - Present Perfect (Passive).
- প্রশ্নে ভবিষ্যৎ কালের কথা উল্লেখ আছে, এখানে অন্যান্য অপশনে Present, Past form এ দেওয়া আছে।
- তাই বাকি অপশনগুলো সঠিক নয়।

Source: A Passage to the English Language, S.M. Zakir Hussain.