We must take care of all living species on earth'. the right passive voice?

• ক All living species on earth can be taken care of by us.
• খ All living species on Earth had been taken care of by us.
• গ All living species on earth might taken care of by us.
• ঘ All living species on earth must be taken care of by us. ✅ সঠিক উত্তর